Authorized Employee Representative.

OSHRC Docket No. 88-0348


Before: FOULKE, Chairman: WISEMAN and MONTOYA, Commissioners.


Industrial Glass, a subsidiary of Tropicana Products, Inc., manufactures glass bottles at its workplace in Bradenton, Florida. In its manufacturing process, Industrial Glass melts sand and other ingredients at a temperature of approximately 2100 Fahrenheit, feeds the molten glass into molds, and then empties the molds onto a conveyor which carries them through stations where the bottles are inspected and tempered. The Industrial Glass employees who operate and maintain the equipment used to manufacture glass bottles in the forming department must work very near the tanks containing the molten glass and the hot bottles on the conveyors, all of which radiate a large amount of heat. The Secretary of Labor, acting through the Occupational Safety and Health Administration ("OSHA"), issued a citation alleging that Industrial Glass had violated section 5(a)(1) of the Occupational Safety and Health Act of 1970 ("the Act"), 29 U.S.C. 654(a)(1).[[1]] because these employees were required to work in excessively high temperatures, exposing them to the hazard of heat stress and to other heat-related conditions.

Industrial Glass contested the citation, and a hearing was held before former Commission Administrative Law Judge Joe D. Sparks. The judge found that, although it was clear that temperatures near the machines were very hot and that working there was uncomfortable, the Secretary had failed to prove that the working conditions constituted a hazard. The judge therefore vacated the citation. The judge's decision was directed for review pursuant to section 12(j) of the Act, 29 U.S.C. 661(j). Having fully reviewed the record in this case, we find that the judge did not err in vacating the citation. We therefore affirm his decision.


There are three bottle-making plants at the Industrial Glass facility in Bradenton. Plants I and 2 are housed in the same structure. while Plant 3 is in another building. In each of the three plants there are four bottle-making machines or "shops." Each of the machines, called "independent section machines," is approximately eight feet high and twelve feet wide. There are eight-section machines, which produce 16 bottles at a time, and ten-section machines, which make 20 bottles at a time. A platform four feet deep runs across the front of the machines for the employees to stand on while they are working near the machines and the conveyor belts.

The ingredients that go into the glass are melted in an overhead tank at a temperature of approximately 2100 F. The molten glass is then led by gravity to each of the machines, where "gobs" of molten glass are fed into the molds. The machine puts two gobs into each mold to form a "parason" (a gob with an air bubble in the center). At this stage, the molten glass has cooled to approximately 1200 F. Compressed air is fed into the mold to distribute the glass evenly inside the mold to form the bottle. Then the mold opens and the formed bottle is pushed onto a conveyor, which carries it through an inspection light, where the operator checks for defects. The bottles come out of the molds onto the conveyor at a temperature of approximately 900 F. By the time the bottles reach the inspection light, the temperature has dropped to about 725 F. From the inspection light, the conveyor carries the bottles to an oven called a "lehr,"where the bottles are "annealed" (alternately heated and cooled slowly to temper them). When the bottles enter the lehr, their temperature is about 600 F.

The plants Operate twenty-four hours a day, seven days a week. With some exceptions, the employees involved in glassmaking work one shift for seven days, rotate to the next shift for seven days, work the third shift for seven days, and then have a week off. They therefore work twenty-one straight days. Seven hourly employees are assigned to each plant: four machine operators, one for each machine; two upkeep mechanics, each of whom is responsible for two machines; and one floor attendant, whose duties are to clean up throughout the plant and to assist the operators and upkeep mechanics. There is also one supervisor, who may spend approximately a third to half of his time on the floor of the plant, but who is generally not involved in the physical operation and maintenance of the machines.

The average tenure of the non-supervisory employees in Industrial Glass's forming department, which is also known as the "hot end," is over ten years. When a vacancy does occur, the company sometimes hires a journeyman machine operator who has experience working in another glass factory; but, more often, the company promotes from within. Employees who have worked in the "cold end" or packaging department of the plant may bid for the job based on seniority. An employee entering the forming department starts as a floor attendant, the job that takes the least training and has least exposure to the intense heat near the machines. The floor attendant assists the operators and learns how to operate the machines on his own. After learning this job, the floor attendant may be promoted to apprentice operator, then to journeyman operator, and finally to upkeep mechanic.

The operators' duties include keeping the machines running smoothly, swabbing the molds with an oil-and-graphite lubricant to keep the bottles from sticking to the molds, inspecting the bottles as they go through the inspection light, taking a number of the bottles off the conveyor for additional testing, and helping the upkeep mechanic when he is working on the machine. The employees' activities vary substantially from day to day and from machine to machine. Each employee receives a 15- minute break in the morning, a 20-minute lunch break, and a 15-minute break in the afternoon (or at corresponding times during other shifts). If there is a jam or a major breakdown, an employee may have to spend extended amounts of time at the hot machines and may have to work through his break, although there is some dispute about how often this occurs.

While the entire plant is hot, the heat varies from area to area. The hottest area is near the machines because that is where the molten glass and newly-made bottles are radiating the heat. Employees can, however, obtain relief from the intense heat nearest the machines. For example, the operator will frequently stand back several feet observing the entire machine operating and watching for malfunctions, a practice called "troubleshooting." An operator who begins to feel that he is being affected by the heat can get the floor attendant or the upkeep mechanic to relieve him. There are large fans, five or six feet in height and width, throughout the plants, with at least one and sometimes two fans per-machine. In addition, there are water fountains located nearby, and there are drinks available from vending machines in the air- conditioned break room.


On August 26 and September 1, 1987, an OSHA industrial hygienist ("the IH") inspected plants 1 and 2. During his initial visit, the IH took readings at several different locations in the general area where the employees worked to determine the Wet Bulb Globe Temperature ("WBGT"), which combines air temperature, humidity, and air movement (which affects cooling by evaporation). It is considered a better indicator of the effects of heat on individuals than just the ambient air temperature, which can be measured by a household thermometer, known as a dry bulb thermometer [[2]]. The WBGT readings ranged from 83.4 to 101.2 F. The IH also took dry bulb readings, which ranged from 91 to 115 F.

The IH made his second visit to Industrial Glass in the late afternoon because he had been told during his first visit that it was the hottest time of day. He stayed about an hour and a half, during which time he took WBGT readings in the vicinity of three different machines. Again, his readings ranged from 83.4 to 101.2 F. During the two visits, he observed the employees' activities and subsequently calculated an estimate of how much energy was required to perform their duties.

Heat stress is caused by a combination of environmental heat and metabolic heat. Environmental heat includes the air temperature, the humidity, the air flow, and the radiant heat emanating from any hot surfaces. Metabolic heat, the heat produced within the body, is increased by physical activity. Because the IH believed after the inspection that some of the employees were exposed to a combination of metabolic and environmental heat that exceeded the threshold limit values ("TLVs") recommended by the American Conference of Governmental Industrial Hygienists ("ACGIH"), the Secretary issued a citation alleging a violation of section 5(a)(1) of the Act. The citation alleged:

(a) Employees in the "hot end" of the glass plant were exposed to the hazard of excessive heat stress during the performance of their duties operating and maintaining the equipment used to manufacture glass bottles. Typically, during the operation of the equipment the worker rotates between his desk, the front end of the equipment and the back side of the equipment.

(b) The Wet Bulb Globe Temperature Index (WBGT-IN) recorded during a survey on September 1, 1987 from a low of 26.5 degrees Centigrade to a high of 38.4 degrees Centigrade. Such exposures may lead to the development of serious heat induced illnesses such as: heat stroke, heat exhaustion, cramps and behavioral disorders, as correlated to guidelines established by the American Conference of Governmental Industrial Hygienists and the National Institute for Occupational Safety and Health.

(c) Among other methods, one feasible and acceptable abatement method to correct this hazard is to provide shielding or barriers that are radiant-reflecting or heat-absorbing, between the heat source and the worker.

(d) Another method would be to limit exposure time by implementing a work-rest regimen which requires mandatory, regularly scheduled breaks for employees in the "hot end."

(e) A water supplementation schedule presented in such a way employees are stimulated to drink five to seven ounces of liquid every fifteen to twenty minutes will serve to augment any control measures used.

(f) Other considerations include physical fitness and acclimatization of employees, as well as the type of clothing worn when working in hot environmental conditions.

(g) Training of employees in the recognition and treatment of heat related illness and the effects of non-occupational factors such as: drugs, alcohol, and physical fitness is also recommended.


In order to prove it violation of section 5(a)(1), the Secretary must establish that: (1) there was an activity or condition in the employer's workplace that constituted a hazard to employees: (2) either the cited employer or the employer's industry recognized that the activity or condition was hazardous; (3) the hazard was causing or likely to cause death or serious physical harm: and (4) there was a feasible means to eliminate the hazard or materially reduce it. Coleco Indus. Inc., 14 BNA OSHC 1961, 1963, 1991 CCH OSHD 29,200 p. 39.070(No. 84-546. 1991).


Much of the hearing was devoted to expert testimony. In addition to the testimony of the IH, the Secretary presented Dr. Wilbur Spaul, a consultant who holds a Ph.D. degree in public health and is a specialist in industrial hygiene, concentrating in heat stress. The company presented two expert witnesses of its own. The three outside experts and the IH all agreed that heat stress is a combination of environmental or ambient heat conditions (the heat in the air, the humidity, and the air velocity) and the internal or metabolic heat Produced by the activity being performed ("the workload"), less the cooling effects of evaporation.


In addition to taking temperature measurements, the IH had estimated the metabolic heat generated by the employees in performing their duties. To do this, he observed the employees performing their jobs and estimated their energy expenditure using tables in a booklet entitled Threshold Limit Values and Biological Exposure Indices published by the ACGIH. The IH stated that he considered the work to be light to moderate and estimated the metabolic workload to he about 396 kilocalories ("Kcals") per hour, which exceeded the limits for exposure to combined environmental and metabolic heat contained in the ACGIH booklet. Although the IH stated that he relied on his professional judgment and his previous experience in making this kind of assessment, he admitted that he had no actual training in workload assessment and that he had performed such an evaluation only once before, in a case that had not been litigated. After acknowledging that the employees had given him widely varying estimates of the amounts of time spent performing various chores, he admitted that the figure he arrived at was simply his estimate of the energy being burned and that it may not be an accurate reflection of the actual workload.

The consultant retained by the Secretary, Dr. Spaul, testified that he went to Industrial Glass' plant and performed "a very brief field evaluation," spending approximately an hour and a half in the forming department, during which time he took temperature readings of his own. His observations indicated that the operators divided their time approximately equally at the operator's station, the operator's work bench, and at the machine, where they check, adjust, and swab the machine. Using a psychrometer to determine the WBGT, he took readings at these three locations around machine number 8, plus readings in front of the fan in that area. He also took readings at the same locations around machine number 7, as well as readings in the break room and in the shade outside the building. His measurements near the machines had a particularly high globe reading, which indicates that there is a high radiant heat load emanating from the machines and the bottles.

At the hearing, the expert presented an exhibit which displayed his temperature measurements at these locations. That exhibit shows the air temperature measured by a dry bulb, the air temperature measured by a wet bulb, the temperature measured by the globe, air velocity, and the WBGT reading, which is calculated by adding seven tenths of the wet bulb reading to three tenths of the globe reading. His WBGT readings ranged between 73.3 F in the break room to 104.4 F at the operator's station next to machine number 7. He stated, however, that there are many indexes that can be used to determine the likelihood that heat stress will occur, and that he does not use WBGT readings when he is retained by a company to evaluate the feasibility of engineering controls in its plant because there are better indicators.

As part of his analysis, Dr. Spaul also estimated the energy being expended by the employees to do the work. Using the operations performed at the locations where he took temperature readings. he calculated a time-weighted average of the environmental heat load and a one-hour time-weighted average of the metabolic workload. First he estimated the work-rest schedule of the operators, based on his observations of the employees' activities during his visit to the plant and his subsequent telephone conversations with the Industrial Glass safety director. He estimated that, in a typical hour, the operators would spend twenty minutes at the work bench, twenty minutes at the operator's station, and twenty minutes at the machine. Relying on these estimates of the time spent on each task, he created a 20-20-20 model and calculated the one-hour time-weighted average WBGT readings for the areas around machine number 7 and machine number 8, using the WBGT temperatures he had taken around both machines. Based on his estimate of the work activity, he calculated that the time-weighted average WBGT reading was 98.1 F around machine number 7 and 95.4 F around machine number 8.

After he had spoken to the Industrial Glass employees, Dr. Spaul checked with the safety managers of other glass manufacturing plants to confirm that the employees' estimates of the time spent doing each task sounded reasonable. Based on these conversations, he calculated three other one-hour time-weighted WBGT exposures for machine number 8, using different estimates of how long the operator spent at each of the three locations measured. Two of these calculations included a provision for time spent by the operator near the fan. In each of his four sets of calculations, the time estimates are in multiples of five minutes.

Using the three locations he had used in his calculations of WBGT exposure, Dr. Spaul evaluated the tasks performed at each of the positions and estimated the workload for each task, performing two sets of calculations to account for the different estimates of the time spent at each location doing the tasks performed there. He also did two sets of workload calculations that allowed for time spent near the fan. His calculations produced a range of energy burned between 190.5 and 312.5 Kcals per hour. When he completed these calculations, Dr, Spaul had four one-hour time-weighted averages for metabolic and environmental heat, as shown in the table below:

Operator's Work Bench Machine Fan WBGT Kcall/hr
Station (F)
20 min (98.4) 20 min (92.4) 20 min (95.5) 95.4 210 - 290
15 min (98-4) 20 min (92.4) 25 min (95.5) -- 95.2 212.5 - 312.5
15 min (98-4) 20 min (92.4) 20 min (95.5) 5 min (86.3) 94.4 201.5 - 242.5
15 min (98.4) 20 min (92.4) 15 min (95.5) 10 min (86.3) 93.7 190.5 - 250.5

Dr. Spaul then compared his environmental and metabolic heat quantities with those in the graph in the ACGIH booklet and determined that all his combined environmental and metabolic heat figures that he arrived at exceeded the limits on the ACGIH graph. He therefore concluded that the conditions at Industrial Glass exposed the operators to the hazard of heat stress. Dr. Spaul testified that Occupational Exposure to Hot Environments, Revised Criteria for a Recommended Standard, 1986 edition, published by the National Institute of Occupational Safety and Health of the Department of Health and Human Services ("NIOSH"), and the Engineering Field Reference Manual published by the American Industrial Hygiene Association ("AIHA") also indicated, based on his figures, that the operators were exposed to the hazard of heat stress.

On cross-examination by the company. Dr. Spaul agreed that there is a considerable amount of variation in the temperatures throughout the forming department.  Dr. Spaul testified that he did observe employees working at a number of locations where he did not take temperature readings, including the water fountain, the weighing scale, and the catwalk behind the machine. As a result, he could not say what levels of hear the employees were exposed to at those locations.

Dr. Spaul stated that the company must have known that its employees were exposed to a hazard because the employees complained to management about the heat and because the company had provided certain controls to limit heat exposure, such as insulation on the furnaces and melting tanks, large fans, water fountains nearby, and electrolyte drinks available in the vending machine in the air-conditioned break room. In addition, electrolyte replacements tablets and drinks were available from the nursing staff. Dr. Spaul expressed the view, however, that these efforts were inadequate.


The company presented two experts, Dr. Bertram Dinman and Dr. Stephen Horvath, both of whom were consultants on the panel that reviewed the NIOSH recommended standard and were contributors to Patty's Industrial Hygiene and Toxicology, a widely-used treatise in the field. Dr. Dinman is a physician who also holds a doctorate in occupational medicine and has been a professor in the fields of public health, occupational medicine, and industrial hygiene. He was an advisor to the military on environmental hygiene, including heat stress, and for several years was medical director, then vice president for health and safety of Alcoa, which has many employees exposed to high temperatures in its aluminum smelting operation. Dr. Horvath holds a pH.D. degree in medical science from Harvard, where he conducted research on human reactions to environmental stresses, including heat. He performed the same kind of research for the military during World War II, and he was subsequently on the faculties of a number of medical schools. He also worked for Alcoa, where he and Dr. Kinmon worked together on the problems caused by hot environments.

At Dr. Kinmon's suggestion, Industrial Glass had one of its senior industrial engineers conduct a time motion study of an operator's activities. He performed an 8-hour study, covering four hours on two consecutive days, observing the operator of machine number 8, the same machine observed by the Secretary's expert, and videotaping his activities. He identified fourteen specific tasks that were performed several times during the course of the study plus miscellaneous tasks that were not repeated, all of which he pin into one category. Listing these activities, he then used a stopwatch to measure how much time the operator spent during the 8-hour period performing each task. He also determined how many times each task was performed during the study. Using this information, he was then able to determine the amount of time spent, on the average, on each task per day and per hour.

The time motion study contains diagrams of the area where it was conducted, identifying where each of the tasks was performed. It also contains a breakdown of how many minutes were spent on each of the tasks for each hour of the study and two composite typical hours. one with and one without a break. The engineer admitted that averaging the times would not give an accurate picture of the operator's activities, because it eliminates the peaks and valleys of certain activities, but he stated that he did not observe a great variance from hour to hour during the periods studied. Throughout the study, there were the sort of minor breakdowns and jams that occur routinely, and the machine did have a breakdown on one of the days, requiring more activity close to the machine, the source of the heat. In contrast to Dr. Spaul's 20-20-20 model, the fourteen specific tasks identified by Industrial Glass' time/motion study required between 20 seconds and 3 minutes,10 seconds per occurrence. and required a total of between 3 minutes and 1 hour, 40 minutes over the course of an 8-hour shift.

Both of the experts retained by Industrial Glass visited the plant. One of them, Dr. Dinman, observed the operation for between four and five hours, while the other, Dr. Horvath, observed the last three or four hours of one shift and the first two hours of the next shift. Both questioned the operators about their activities and satisfied themselves that the conditions they were observing were typical. Each of them studied the videotapes made during the time/motion study to help them determine the precise motions involved in the activities of the operator.

Using the videotapes and the time/motion study, the experts each performed a workload analysis similar to the one performed by Dr. Spaul. They analyzed each task, breaking it down into its various motions, determining the workload for each element of each task, then adding them to get the workload for the entire task. The Kcals for each task were multiplied by the minutes per hour spent performing that task, and those products were then totaled. Dr. Dinman calculated the operator's exertions as ranging from 132 to 167 Kcals/hour, while Dr. Horvath calculated them at 136 to 138 Kcals/hour. Based on these figures, the company's experts both concluded that the operator's actual metabolic workload was substantially less than estimated by the IH and Dr. Spaul. Both of them stated that, even if they accepted the Secretary's temperature measurements and calculations of the environmental heat load as correct. [[3]] the employees were not exposed to a total heat load great enough to cause heat stress.

Explaining how he reach his conclusion, the first expert, Dr. Dinman, stated that it is important to identify all locations where an employee would work during the course of his job and to determine the temperatures at each of those locations. He explained that, if the temperatures vary from location to location, it is necessary to determine how much time the employee spends in each location. Dr. Dinman testified that the time/motion study was useful to determine the locations where the employees worked, the amounts of time spent in each location, and the metabolic heat generated by the employee's activities.

The other expert, Dr. Horvath, stated that a person's heart rate is an indicator of how much he is exerting himself. While he was at the Industrial Glass plant, Dr. Horvath took the pulse of the operator on a number of occasions, comparing the rates after certain tasks with the resting rate. The difference was so slight that he concluded that the operator's duties were not strenuous. Dr. Horvath reinforced this conclusion in the laboratory, where he and his staff copied the various motions involved in some of the operator's tasks, measuring the carbon dioxide produced. Even though the lab had highly sophisticated equipment, he could not measure enough of an increase to be considered significant.

Dr. Horvath stated that he had been involved in numerous time/motion studies himself and could tell that the company's in-house study had been carefully done.  Dr. Horvath noted that he considered the company's study "informative," but he knowledge that a longer study would likely have included a wider range of conditions and tasks not performed frequently.  He did, however, have the benefit of a 12-day time/motion study performed by another glass company which had retained him as a consultant.  That company used the same kind of machinery as Industrial Glass, and its employees' activities were similar.  He testified that his preliminary analysis of that study produced a metabolic expenditure very close to the figures he got in this case.

Both of the experts presented by the company had worked for Alcoa, where there were high levels of heat radiated by large amounts (750 pounds) of molten aluminum.[[4]]  The temperature of the bottles coming out of the molds is approximately the same as that of the molten aluminum with which the two witnesses were familiar.  Both of the company's experts had served on the panel which had developed the NIOSH recommendations and were familiar with the studies underlying the figures and the process by which figures had been decided.  Both were very critical of the series of compromises involved in developing the recommendations, asserting that there was little or no scientific basis for some of the recommendations, particularly the conclusion, represented by the curve on the graph, that continuous work at an energy expenditure below the 200-Kcal level exposes employees to heat stress.


The Secretary presented as witnesses a number of Industrial Glass employees, who testified that they had experienced various ailments that they attributed to the heat, including headaches, dizziness, nausea, muscle cramps, and problems with their vision.  For example, the union president testified that he had fainted twice.  The first occasion was approximately ten years before the hearing, when he felt hot, went to get a drink of water, and collapsed.  The second incident occurred about a week before the hearing was held, while he was in the employees' shower room talking to some other employees.  He felt weak and told the other employees that he was going into the other room to lie down.  As he started to go into the other room, he collapsed.  On both occasion's, the company's nursing staff was called and treated him.  On the second occasion, the nurse called an ambulance for him, but he refused to go to the hospital. In general, the employees testified, they did not seek treatment from the company's nursing staff or from a physician.  In response to an OSHA subpoena, the nursing staff reviewed its records and found only seven reported incidents in a 4 1/2 year period which might be attributable to the heat.[[5]]

Some of the employees testified that, when they or other employees had brought thermometers to the plant from home and had placed them around the work area, some of the thermometers had hit their maximum readings, and that one that was calibrated up to 180 F reached 160 F. [[6]]  There was also testimony that the clothing of some employees had caught fire from the heat.  A witness for the company, who had been an operator himself, testified, however, that clothing cannot catch fire solely from the heat; it can happen only if the clothes come into contact with the hot glass when the bottles come out of the mold onto the conveyor.  In his experience this occurs only rarely. [[7]]


As noted above, to prove a violation of section 5(a)(l), the Secretary must show that the employees were exposed to a hazard in the workplace.   The Secretary presented both expert and employee testimony addressing this element.   Having reviewed the record, we find that the Secretary has not established by a preponderance of the evidence that there was a hazard present in the Industrial Glass forming department.

The citation identified the hazard as "excessive heat stress" (emphasis added), perhaps in recognition that at least some amount of heat stress is an inevitable part of this operation.  In her subsequent complaint, the Secretary alleged: "Respondent violated 5(a)(l) of the Act in that it allowed its employees in the 'hot end' of the glass plant to be exposed to excessive heat stress while operating and maintaining equipment used to manufacture glass bottles."  The bulk of the evidence the Secretary presented to prove that there was a hazard was the expert testimony that the employees were exposed to a combination of environmental and metabolic heat that was excessive because it exceeded the limits permitted under the NIOSH, ACGIH, and AlHA documents, while the company's primary evidence that there was no hazard is the testimony of its two experts.  All three expert witnesses were highly qualified, and the opinions of the company's experts are in direct conflict with those presented by the Secretary's, making it difficult to evaluate the voluminous evidence in this controversy.  Had the company not presented such a strong rebuttal of the Secretary's case, we might have found the testimony of the Secretary's expert that the employees were exposed to the hazard of heat stress to be persuasive.

Two factors weigh heavily in our decision in favor of the company, however: the eminence of its experts; and the fact that their testimony was based on a time/motion study that identified four or five times as many tasks as were assumed in the model relied on by the Secretary's expert.  In view of the company's time/motion study, we simply cannot give much weight to the portion of the Secretary's evidence that was predicated on the assumption that the operators spent twenty minutes of each hour at one location performing one task, twenty minutes at another location performing another task, and twenty minutes in a third location doing a third task.

It is clear from the record that the operator's duties are much more varied than assumed by Dr. Spaul's -20-20-20 model and that, contrary to the assumption by the Secretary's expert, an operator spends far more time in locations that are removed from the bottles and the machines, which are the source of the heat.  As Dr. Dinman testified, a study which records the operator's minute-by-minute activities and analyzes them job component by job component will be more precise than the rough estimates relied on by the Secretary.[[8]]  Because we have no heat measurements for these other locations, some of which are several feet from the machines, we cannot determine what the temperatures are in those locations.  Since we are not able to ascertain the levels of the employees' heat exposure at each work station, we cannot make any determination of their overall environmental heat exposure.

Even if we assume arguendo that exceeding the exposure limits set out in NIOSH's recommended standard and in the ACGIH and AIHA publications would prove that there was a hazard within the meaning of section 5(a)(1) based on the information in this record, we are unable to determine whether an employee's total heat exposure would in fact exceed those levels of heat exposure.  Because the testimony of the Secretary's expert was based on temperature readings that did not accurately reflect the movements of the employees around the forming department, the Secretary has not carried her burden of establishing that the levels of environmental heat were excessive.

We are also unable to give much weight to the calculations of metabolic heat by the Secretary's expert, who testified that he frequently does physiological workload assessments of the sort performed by Dr. Horvath at the plant and in the laboratory, but conceded that he elected to use the tables in this case because such assessments are time-consuming and tedious.  Dr. Horvath testified that it was it mistake for the Secretary to assume so few tasks.  The company has argued that the Secretary's calculations of the employees' metabolic workload were based on inadequate information because they assumed only three or four activities.  The judge agreed with that argument and we do as well.  The company's experts, working separately, both arrived at significantly lower workload levels.  Given the more detailed information on which their analyses were based and the more precise methods used to assess the energy expenditure, we are inclined to give them more weight than the calculations of the Secretary's expert.  We note that Dr. Spaul and the IH both admitted that the employees gave them widely varying estimates of they time they spent performing the different tasks on which they based their metabolic heat estimates.  We therefore accept the metabolic heat estimates of the company's experts rather than those of the Secretary's expert and the IH.

The Secretary has emphasized that one of the company's experts testified that the work done by an operator was about twice as strenuous as driving a car.   For a number of reasons we are not certain exactly what that testimony means or how much weight to give.

First, the witness also testified hat the figure given for driving a car in the ASGIH booklet seemed much too high to him.[[9]]  In addition, both parties presented evidence that there was a base figure for a body at complete rest, although the figures presented by the Parties differ.  Neither party, has explained whether "twice as strenuous" is calculated by subtracting this base number first.  Then doubling the remainder, of by doubling the actual figure for driving a car. The Secretary's reply brief simply doubles the figure given in the ACGIH booklet, but it is not at all clear to us that doubling is the proper way to make the calculation.   The calculations in the NIOSH recommendation suggest that the basal metabolism remains constant and that additions are made to that figure depending on the activity and the position in which the activity is performed.  The ACGIH document is not so clear, however, We therefore do not know whether the calculation in the Secretary's brief is correct.  Because we cannot determine on this record exactly what "twice as strenuous" means, we do not know how much weight to accord that statement.

The Secretary has argued that one of the company's supervisors testified that the work in the forming department was comparable to heavy construction, which he had previously done.  A review of that testimony, however, reveals that the witness was not referring to how strenuous the work was.  What he said was that the heat was comparable to being on a metal roof in the summer.  His testimony therefore does not contradict that of the company's experts.

The Secretary has further asserted that the NIOSH, ACGIH, and AIHA documents establish a maximum WBGT level of 86 F for employees performing continuous light work at a level below 200 Kcals per hour.  We find, however, that, even if we assume that exceeding this recommended limit would he a hazard, the Secretary has not established that the cited employees were performing "continuous work".   Although the Secretary's expert testified that it was his impression that the employees were under a continuous workload, the testimony of the employees shows that, to the contrary, they do rest between activities, and they can get away from the source of the heat even while they are performing their duties.  The Secretary's expert may have believed that the operators' activities placed them in the "continuous work" category, but the record makes it clear that working without taking an official break within the meaning of the employment contract is not the same as working without pause or rest.  The employees did not engage in constant action but took brief breaks between tasks and even rested momentarily during a task.  We therefore find that Industrial Glass's employees did not fall within the "continuous work" category as the Secretary claims.

We must note that we would be hesitant to hold that exceeding those levels is, in and of itself, proof of exposure to a hazard.  The Secretary asserts that they are the dominant guidelines on heat stress and are followed by all professional industrial hygienists.  Dr. Spaul, the Secretary's own expert witness, testified, however, that all three documents were essentially copied from each other and that they all contained a substantial safety margin.  While it would be very appropriate for the Secretary to include a safety margin in an OSHA standard, the presence of a safety margin in the documents she relied on to prove a hazard here gives us reservations as to whether evidence that the limits in the NIOSH document were exceeded would, in fact, prove that there was a hazard.[[10]]  Furthermore, Dr. Horvath testified that some of the work on which the NIOSH curves were based had subsequently been discredited to a large extent, and both of the company's experts testified that there was inadequate scientific information to support some of the assumptions shown on the graphs in these documents.  We therefore have considerable reservations about basing a violation of section 5(a)(l) or those guidelines.  Because we are deciding this case based on the insufficiency of the Secretary's evidence, however, we need not decide whether a violation of section 5(a)(l) would have been established if the Secretary had proved that the limits in the documents had been exceeded. [[11]]

Having concluded that the Secretary failed to establish the presence of a hazard by expert testimony, we must examine the other evidence presented by the Secretary, namely the testimony of the employees.  While the employee testimony regarding the difficulties they experienced because of the hot working conditions troubles us because it clearly shows that this is an uncomfortable working environment and that employees do suffer from the effects of the heat, [[12]] the citation's identification of the hazard as excessive heat stress suggests that the Secretary recognizes that some degree of discomfort is inherent in the job.  The testimony as to headaches, dizziness, nausea, fatigue, muscle cramps, and even the two instances of fainting must be balanced against the fact that many of the abatement measures sought by the Secretary were already in place to one degree or another.

We note that Congress intended that an employer's duty to free its workplace of hazards under section 5(a)(l) to be an achievable one.  Nat'l Realty & Constr. Co. v. OSHRC, 489 F.2d 1257, 1265-66 (D.C. Cir. 1973).  Here, Industrial Glass had installed insulation on the melting tanks.  Near every machine, there was at least one large blower and a water cooler.  The company had moved the machines farther apart, which reduced the concentration of heat.  There were electrolyte drinks available to the employees, both through the nursing staff and in it vending machine in the break room, which was air conditioned.  The nurses also had electrolyte tablets available for any employee who suffered from the effects of the heat.   Before a new employee was hired for the forming department, the nursing staff took a medical history and performed an assessment of the individual's medical fitness to work in a hot environment.  If they did not find that the candidate was medically suitable, they informed the personnel department.  There was also a de facto acclimatization by virtue of the one-week orientation that was part of a new employee's training.  There wits already established a "buddy system" among the employees of watching out for each other and relieving, an employee who began to be affected by the heat. Also, there was testimony that, on at least one occasion the foreman sent an employee home when he had difficulty with the heat rather than allow him to be exposed to excessive heat.  We realize that these measures do not absolutely guarantee that an employee will never suffer from exposure to the heat, but the record shows that it is virtually impossible to eliminate all exposure to high temperatures in this Job.[[13]]

We recognize, as the secretary apparently did, that the working conditions in the forming department are, to some extent, an inevitable part of this kind of work.  The employees who testified appear to have considered the conditions to be uncomfortable rather than hazardous. The employees who testified that they suffered various ailments from the heat admitted that they did not seek any medical help, and the union officer who fainted twice refused to go to the hospital even though an ambulance had been called for him.  It therefore appears that the employees considered the heat conditions to be more of a discomfort than a health hazard.[[14]]  As noted above, the jobs in the forming department, which involve higher pay, are considered desirable and are highly sought after by Industrial Glass employees who work in the packaging department.  They are filled on the basis of seniority unless an experienced glassmaker is hired.

Accordingly, based on the expect testimony and the measures present in the forming department to reduce employee exposure to heat and to alleviate its effects, we conclude that the Secretary has failed to prove by a preponderance of the evidence that the working conditions in the forming department presented a hazard within the meaning of section 5(a)(1) of the Act.


We recognize that excessive exposure to heat can be a hazard, but the record in this case shows that the company has made an effort to alleviate the effects of the hot working conditions in the forming department.  We find here that the Secretary has failed to establish by a preponderance of the evidence that the working conditions in the forming department constituted a hazard that was likely to cause serious harm to the health of the employees.  For these reasons, we conclude, as the judge did, that the Secretary has failed to prove that Industrial Glass committed a violation of section 5(a)(1) of the Act by exposing its employees to the hazard of heat stress.

We therefore hold that the Secretary has failed to carry her burden of proving that there was a heat stress hazard in the Industrial Glass forming department.  Accordingly, we affirm the judge's decision vacating the citation.

Edwin G. Foulke. Jr.

Donald G. Wiseman


Velma Montoya

Dated: April 21, 1992



Respondent, and


Authorized Employee Representative.

OSHRC Docket No. 88-348


Stephen J. Simko, Jr., Esquire, Office of the Solicitor, U. S. Department of Labor, Atlanta, Georgia, on behalf of complainant.

William B. deMeza, Esquire, Holland and Knight, Tampa, Florida, on behalf of respondent.
Mr. John Ward, President, Glass Molders, Plastic, Pottery and Allied Workers, Local 208, Bradenton, Florida, on behalf of the authorized employee representative.


SPARKS, Judge:     Respondent, Industrial Glass, contests a citation for the serious violation of section 5(a) (1) [[1]] of the Occupational Safety and Health Act ("Act") for allowing its employees in the Forming Department to be exposed to excessive heat stress while operating and maintaining equipment used to manufacture glass bottles. The case was ably tried and briefed by counsel, and extensive testimony and documentary evidence were received into the record.


Industrial Glass is a division of Tropicana Products, Inc., which operates several facilities located on 214 acres of land in Bradenton, Florida. Industrial Glass manufactures glass bottles in various sizes in three glass plants in Bradenton, where approximately 400 glass unit workers are employed (Tr. 28- 29).

The Forming Department in Plant 2 contains four independent sections ("I.S.") glass making machines called "5 Shop," "6 Shop," "7 Shop," and "8 Shop" (Tr. 97-98, 773).  Employees in the Forming Department work seven-day rotating shifts. They work one shift seven straight days and then rotate to another shift or off duty. Industrial Glass runs three shifts each day, seven days a week. Shifts are 8:00 a.m. to 4:00 p.m., 4:00 p.m. to 12:00 a.m., and 12:00 a.m. to 9:00 a.m. Plant 2 employs seven hourly employees per shift: four operators, two upkeep mechanics, and one floor attendant (Tr. 26-27, 783, 824-825).

Plant 2 shops produce between 100 and 294 bottles per minute (Tr. 39). To produce the glass bottles, the raw sand batch and glass cullet mixture is melted in the tank above the I.S. machine. The glass at that point is between 2000 and 2100 degrees Fahrenheit. The molten glass drops down and is sheared into gobs through the feeder into the molds. Two gobs drop into each mold. The gob is formed into a parason, a gob with a bubble in it, and a finish, the part of the bottle where the bottle where the cap is attached. The bottle is now upside down. Air is blown on the outside to form and cool the glass. The glass is then inverted into the mold. The mold closes around it and compressed air is blown into the bottle to form it. The mold then opens and the bottle is pushed onto the conveyor and proceeds down the inspection light and the lehr. The lehr performs annealing, a gradual cooling of the glass. The glass is molded at about 1200 degrees Fahrenheit. When it is placed on the conveyor, its temperature is between 700 and 900 degrees Fahrenheit. The smaller bottles are cooler. The largest bottle made on these machines is a 1.75-liter liquor bottle. The temperature of this bottle is about 850 degrees Fahrenheit coming onto the conveyor. At the inspection light, the temperature of the bottle drops to 725 degrees Fahrenheit; and, when entering the lehr, the bottle temperature is 600 degrees Fahrenheit (Tr. 775-783, 800-801).

The operators' duties include observation of the operation of the glass making machine, quality control checks by testing bottles, swabbing the molds with graphite oil front and back (doping), assisting on clearing jam ups and helping the upkeep men to change molds and repair machines if needed. Operators usually work 1.5 to 5 feet from the molds (Tr. 40-46).

The upkeepmen's duties include working on and repairing machine breakdowns, changing molds, fixing defects in the glass, working on the tanks that melt the glass, repairing and maintaining the feeders and relieving operators for breaks. Each upkeep person is responsible for two machines. Duties require these employees to be next to the machines (T. 59-61, 259-260).

The floor attendants' duties are to clean glass from underneath the machines, keep glass off of the floor, keep the barrels dumped out, and see to the needs of the operators and upkeep people. Their work often requires the floor attendants to work close to the machines (Tr. 287-288).

Forming Department employees receive two 15-minute breaks and a 20-minute lunch break during each eight-hour shift (Tr. 107).The break room is air conditioned (Tr. 104).

Industrial Glass employs four registered nurses who work on the plant premises. The nurses do not work the 12:00 a.m. to 8:00 a.m. shift or any weekend shifts (Tr. 26-27). Industrial Glass does not have physicians on the premises but uses doctors on call in the community for medical conditions and accidents or injuries (Tr. 149).

OSHA Industrial Hygienist Byron Blanke began his inspection of Industrial Glass' facilities on August 26, 1987, pursuant to a complaint received in his office (Tr. 368). Blanke took temperature measurements at several locations throughout the facilities. He returned to the facilities on September 1, 1987, and took additional readings (Tr. 368-371). As a result of Blank's inspection, Industrial Glass was issued a citation for the violation of 5(a)(1) on January 13, 1988.


In order to establish a section 5(a)(1) violation, the Secretary must prove: (1) the employer failed to render its workplace free of a hazard, (2) the hazard was recognized either by the cited employer or generally within the employer's industry, (3) the hazard was causing or was likely to cause death or serious physical harm, and (4) there was a feasible means by which the employer could have eliminated or materially reduced the hazard.

The Duriron Co., 83 OSAHRC 22/A2, 11 BNA OSHC 1405, 1407, 1983 CCH OSHD 26,527 (No. 77-2874, 1983), affirmed 750 F.2d 28 (6th Cir. 1984).

The Secretary alleges that Industrial Glass failed to render Plant 2 free of excessive heat in the Forming Department, where operators, upkeep mechanics, and floor attendants were exposed. Industrial Glass contends that while conditions in the Forming Department may have been uncomfortable, they did not rise to the level of a recognized hazard likely to cause death or serious injury. If excessive heat exposure did exist, Industrial Glass' employees were put at a significant risk.

Exposure to excessive heat can result in heat exhaustion and heat stroke. At high temperatures, the body circulates great amounts of blood to the skin in an effort to eliminate heat through perspiration. As a result, less blood is circulated to the body's vital organs, including the brain. Heat exhaustion can lead to dizziness, nausea, and eventual collapse. If not treated promptly, a person suffering from neat exhaustion could suffer brain damage.

Beyond heat exhaustion is heat stroke.... [D]uring heat stroke the body stops sweating, making it impossible to eliminate heat. The body temperature may rise to a dangerously high level and cause death.

Id. at 1406.

Several Industrial Glass employees testified as to the conditions in the Forming Department. They established that, although their union contract since 1983 had called for a heat relief break in addition to the morning, lunch, and afternoon break, operators did not start receiving a heat relief break until one and a half months before the August, 1988, hearing. Upkeep mechanics and floor attendants were still not receiving heat relief breaks at the time of the hearing (Ex. C-1, C-2; Tr. 64, 187, 215, 317). The employees also testified that at one time the employees in the Forming Department started bringing in various home thermometers, including baking and pool thermometers, and hung them around the work area. The thermometers were eventually taken down by supervisory personnel, but not before the employees observed readings of 140 to 160 F. (Tr. 118, 190-191, 219-225, 269).

Several employees related instances where they experienced discomfort which they attributed to the excessive heat. John Ward, an upkeep mechanic and union representative, testified that just two weeks prior to the hearing, he fainted due to the heat after working six and a half to seven hours in front of the machines (Tr. 73-74):

I was talking to several of my committee members in the shower room. I had a bad headache, I was sweating, I was burning up, I got severe pains in the back of my head, and I told them I was going to lay down. I started into the other room in the shower room to lay down and I couldn't see. And I ended up on the floor.

Ward was treated by a staff nurse. He did not consult a physician regarding this incident so there was no confirmation that his distress was attributable to excessive heat in the workplace (Tr. 124-125).

Ronald Sykes worked as a floor attendant for Industrial Glass for six months, including the summer of 1987. He described the conditions as follows (Tr. 189):

Well, especially this time of year, it's real hot. Once in a while, you'd have a kind of dizzy spell. Like, you know, it would be so hot, you would just have to back away and just stop for a while . . .  You were always soaked with sweat or something in there . . . . Once in a while maybe, .you know, depending on, I guess, the humidity or whatever, just different things, dizziness, stuff like that.

Sykes never went to the staff nurses or sought medical treatment with regard to any of the symptoms he mentioned (Tr. 192). The company provided water, fans and an air conditioned break room, but the environment near the machines was extremely hot.

The testimony of the employees establishes that the heat in the Forming Department at times was oppressive but standing alone, does not prove that the heat was so excessive as to excessive injury. The thermometers that the employees brought in were for home use and not calibrated to the degree of accuracy necessary to establish their readings. Helen Heatherington, a staff nurse for Industrial Glass for eight years, testified that employees from the Forming Department sought treatment from the nursing staff less frequently than employees from other departments (Tr. 175). A medical record review prepared by the head nurse, Edna Davis, for the period from January 1984 to June 1988, disclosed that a total of five employees came to) the nurses a total of seven times complaining of symptoms that may have been heat related (Ex. C- 12). None of these employees ever consulted a physician with regards to their complaints, and no medical evidence exists that could support the employees contentions that their complaints were caused by excessive heat. As Industrial Glass pointed out at the hearing and in its posthearing brief, symptoms of heat stress are similar to symptoms of other ailments, including the flu and hangovers.

Turning from the employee witnesses' testimony, then, it is necessary to evaluate the testimony of the expert witnesses, who sought to calculate the amount of heat stress present in the Forming Department. The standard instrument for testing heat stress is the Wet Bulb Globe Thermometer ("WBGT"). The WBGT takes into account humidity and air movement (the natural wet bulb reading ("NWB")), and air velocity and air temperature (the black globe reading ("GLOBE")] (Ex. C-6, pp. 3,150; Tr. 464). The calculation for WBGT for indoors is (Ex. C-22, p.5):

WBGT = 0.7 NWB + 0.3 GLOBE

On September 1, 1987, Compliance Officer Blanke took eight measurements in the Forming Department, which ranged from a low of 83.4 F. to a high of 101.2 F. for WBGT (Ex. C-15). Dr. Wilbur Spaul, the Secretary's expert witness, who holds a Ph.D. in Environmental Health Sciences, visited Plant 2 on June 15, 1988, and took his own WBGT measurements (Tr.469). Dr. Spaul was knowledgeable, conscientious and convincing. His testimony was defective only in that he did not make or was not allowed to make, the detailed investigative findings as was respondent's expert witnesses. Spaul calculated that the average 'WBGT for machine No. 8 was 4 F. based on a one-hour time-weighted average (Tr. 507, 510)

Dr. Spaul spoke with Steven Looby, the safety manager for Industrial Glass, who informed Spaul that during an average hour, operators spent 20 minutes at the operators' work station on the platform, 20 minutes at the test stand, and another 20 minutes in the general area of the machine (Tr. 506). Based upon Looby's estimate and his conversations with employees, Dr. Spaul concluded that operators were under a continuous workload (Tr. 490). Dr. Spaul also called several glass plants and spoke with the safety managers to get their estimates of their operators' work/rest schedules (Tr. 493). Although information from these sources was helpful, it is not afforded the weight given to the time and motion studies offered by respondent and relied upon by its expert witnesses.

Dr. Spaul used three guidelines in making his calculations after ascertaining the WBGT; (1) the American Conference of Governmental Industrial Hygienists ("ACGIH"), Threshold Limit Values and Biological Indices for 1986-1987 (Ex. C-4); (2) National Association for Occupational Safety and Health ("NIOSH"), "Criteria for a Recommended Standard . . . Occupational Exposure to Hot Environments: Revised Criteria 1986" (Ex. C-6); and (3) American Industrial Hygiene Association ("AIHA"), "Engineering Field Reference Manual" (Ex. R-9: Tr. 473-479). Respondent's expert witnesses questioned the reliability of the guidelines, contending there were inadequate studies to support the conclusions but no reasonable alternative was suggested. They are endorsed by the leading organizations in the field.

Dr.Spaul testified that heat stress is calculated by adding metabolic heat to environmental heat, then subtracting the heat lost through evaporation (Tr. 471- 473). Metabolic workload is calculated in kilocalories per hour ("Kcal/hr"). AIHA, ACGIH, and NIOSH define light work as work up to 200 Kcal/hr (Ex. C-4, p. 70). Dr. Spaul determined that the average level of energy required to perform the operators' job was 200 Kcal/hr (Tr. 518-525). His actual readings ranged from 190 Kcal/hr to over 300 Kcal/hr (Ex. C-22, p. 13; Tr. 490, 492, 495, 510, 519).

ACGIH and NIOSH have established the maximum WBGT to which employees may safely be exposed at any metabolic workload above 200 Kcal/hr. The maximum WBGT for a continuous workload of 200 Kcal/hr is 86 F. (Ex. C-4, p. 72, figure 1). Based upon his calculations of the WBGT and the metabolic workload, Dr. Spaul concluded that the operators in Industrial Glass' Forming Department were exposed to excessive heat (Tr. 469). The weakness in Dr. Spaul's conclusions results from the underlying determination that employees were under a continuous light workload requiring energy use of 200 Kcal/hr.

Industrial Glass presented two expert witnesses, Dr. Bertram Dinman, a Clinical Professor of occupational Medicine, and Dr. Stephen Horvath, a Professor of biomedical Engineering (Tr. 673, 840).. Both men have had and distinguished careers and are highly regarded in the field of heat effects on the human work capacity. They separately evaluated unimpeached time and motion studies which had been made on employees in the Forming Department (Tr. 857). They observed two shifts for four or five hours on two different shifts (Tr. 696). They also reviewed a videotape of an employee operating an I.S. machine (Ex. R-2; Tr. 693, 696-697, 765). Dinman and Horvath calculated a total hour-by-hour metabolic workload by determining that an operator performs 15 separate tasks in his or her job, and assessing the metabolic workload for each of the 15 tasks. The individual workload components were time-weighted and totaled (Tr. 695-702). The greater weight given to the testimony of Drs. Dinman and Horvath is directly attributable to the greater probativeness of the evidence upon which they based their conclusions.

Dr. Dinman found that the operators' metabolic workload ranged from 132 to 167 Kcal/hr. Dr. Horvath calculated the workload to be 136 to 138 Kcal/hr. Both concluded that the metabolic workload was mild (Tr. 857). Dinman and Horvath concluded that employees in the Forming Department were not exposed to excessive heat.

Industrial Glass attacks Dr. Spaul's calculations as invalid and inaccurate. Industrial Glass notes that Inspector Blanke and Dr. Spaul measured temperatures only at selected points around the I.S. machines, and that Spaul only Calculated the metabolic workload for operators, ignoring the exposures of upkeep mechanics and floor attendants. Industrial Glass also points out that Dr. Spaul calculated his time-weighted averages based on rough estimates given by Looby, safety managers at other glass plants, with no showing that their I.S. machines or employee tasks are similar to those of Industrial Glass. While Dinman and Horvath identified 15 separate tasks performed by the operators, Spaul broke down the operators' tasks into only three categories (Ex. -22, pp. 9-11). However, it is concluded that Dr. Spaul's testimony is not convincing only because the facts upon which he relied were inferior in quality and quantity than those available to respondent's experts.

There is much evidence that employees suffered severe heat discomfort, especially during the summertime. Although heat is necessary in the glass making industry, evidence is lacking that respondent did everything possible to alleviate those conditions. But the Secretary has not carried her burden of proof on the essential element that a hazard did in fact exist. Looked at together, it is evident that Industrial Glass' expert testimony was much more specific and comprehensive; and, therefore, more accurate and creditable, than that of the Secretary. The Secretary did not prove that employees in Industrial Glass' Forming Department were exposed to excessive heat so as to establish a hazard under section 5(a)(l). Industrial Glass was, therefore, not in violation of section 5 (a) (l).

The foregoing constitutes the findings of fact in this case.


1. Respondent is subject to the Act and this proceeding.

2. Respondent did not violate section 5(a)(l) of the Act.


The citation and complaint are dismissed.

Dated this 29th day of March, 1989.



[[1]] Section 5(a)(1) provides "Each employer shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or likely to cause death or serious physical harm to his employees."

[[2]] In contrast to a household, or dry bulb thermometer, a wet bulb thermometer has a bulb that is covered by a saturated cloth. This reading is affected by the rate of evaporation, which is determined by humidity and air velocity. Another type of device, the global thermometer, is set in a matte black metal sphere and measures radiant heat. All the global temperatures taken by the IH and the Secretary's expert were higher than the other readings at the same locations, indicating that there is a great deal of radiant heat in the forming department.

[[3]] They did, however, question the Secretary estimates of the employees exposure to environmental heat because the time motion study showed that the employees were not limited to three or four locations.

[[4]] Dr. Horvath noted that one of the difficulties in making an accurate measurement of an individual's heat exposure in a situation like this with a high level of radiant heat is that one side of the person may be exposed to a low level of heat while the other side is exposed to a great deal of heat radiating from the source.

[[5]] Both of the incidents involving the union president fell outside the period surveyed by the nursing staff.

[[6]] Dr. Horvath cast doubt on these readings, however, because he stated that the thermometers should be shielded from radiant heat sources in order to get an accurate reading of the air temperature. He testified that, depending on where the thermometer was placed, heat radiating at it from all sides could give an artificially high reading.

[[7]] The citation alleged the hazard of heat stress. It does not mention burns. While there is some evidence that in employee is more likely to be inattentive and bring his clothing into contact with the bottles if he is suffering the effects of the heat, we cannot say that the citation covers the situation described.

[[8]]The Secretary has argued that a time motion study based on four hours per day over two days is hardly likely to give an accurate reflection of all the conditions under which an operator will work. We agree. All of the experts were in agreement that a study covering a much longer period would have been more desirable. The company's. time motion study is, however, the best evidence we have. It is certainly more accurate than the estimates relied on by the Secretary's consultant who admitted that he would prefer to base his evaluation on observation of the operator's activities for a minimum of five days rather than on his observation for only 1 1/2-hours.

[[ 9]] In the table of energy expenditure, a substantial range is given for activities such as lying at ease, sitting at ease, and casual walking, but a single figure is given for driving a car. It seems to us, however, that the level of energy expended driving an automobile can vary greatly, depending on the type of automobile and the road. For example, it seems unlikely that the same amount of energy would he required to drive a car with automatic transmission and cruise control along a straight, flat interstate highway as would he required to drive a standard shift car along a windy mountain road or in city traffic during rush hour. Given these potentially large differences in the amount of energy required to operate different automobiles under different conditions, we cannot say with any confidence that the parties were talking about the same activity. We also note that, on the table of energy expenditures in the AIHA Engineering Field Reference Manual, on which the Secretary relies. The value given for sitting at ease is substantially higher than the values given for both mechanical typing and electrical typing Because we do not understand this seeming incongruity, we do not know how much authority we can attribute to the contents of this table.

[10] In 1972, NIOSH recommended that OSHA adopt a standard governing exposure to heat, and a panel appointed by OSHA endorsed that recommendation in 1974. Nevertheless, OSHA has not adopted a heat stress regulation but has relied here on the NIOSH criteria and on guidelines issued by two private organizations of industrial hygienists. The essence of the Secretary's allegation is that the heat exposure limits set out in those documents were exceeded and that the employees were therefore exposed to the hazard of heat stress. The NIOSH standard, however, does not have the force and effect of law; failure to comply with it is not in and of itself illegal.

[[11]] Contrary to the Secretary's assertion, the Commission's decision in The Duriron Co., 11 BNA OSHC 1405, 1407 n. 2. 1983-84 CCH OSHR 26,527, p. 33,798 n. 2 (No. 77-2847.1983), aff'd, 750 F.2d 28 (6th Cir. 1984) does not require a difference result. In that case the Commission found the existence of a hazard based upon evidence other than exceeding the limits, in the NIOSH document and was careful to state that the document was considered only for the purpose of establishing that the employers industry had recognized that heat stress was a hazard. Here, the Secretary has attempted to prove that exceeding the limits set in the documents constituted a hazard.

[[12]] The company presented evidence that the effects of heat-related conditions resemble symptoms caused by the flu, viruses, or other ailments. We are inclined, however, to believe that the employees' complaints are more likely than not the result of their very hot working conditions.

[[13]]One of the abatement measure proposed by the Secretary in the citation was a required drinking program for employees in which they would drink water every fifteen to twenty minutes. We note that the company's time motion study shows that the employee studied went to the water fountain to get a drink three times an hour in hours he did not get a break and twice an hour when he did have a break during the hour. It would therefore appear that this measure is in effect already in place.

[[14]]Although this evidence is not controlling it does constitute evidence from the individuals who are most familiar with and most affected by the cited working conditions. See General Motors Corp. 11 BNA OSHC 2062.2066 1984-x5 CCH OSHD 26.961 pp 34.611-12 (No. 78-1443.1984). aff'd. 764 f.2d 32 (1st Cir. 1985). We therefore accord these views some weight and consider them together with the other evidence on the question of whether the Secretary proved that there was a hazard.

[[1]] Section 5(a)(1) of the Act, 29 U.S.C. 654(a)(1), provides:

Each employer shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.