OSHRC Docket No. 268

Occupational Safety and Health Review Commission

August 28, 1974


Before MORAN, Chairman; VAN NAMEE and CLEARY, Commissioners



  VAN NAMEE, COMMISSIONER: This matter is before the Commission on former Commissioner Burch's order directing review of a decision made by Judge Joseph Chalk.   Judge Chalk vacated Complainant's citation for serious violation of section 5(a)(2) of the Occupational Safety and Health Act of 1970 (29 U.S.C. 651 et seq., hereinafter "the Act") which alleged failure to comply in any of four separate locations with the standard published at 29 C.F.R. 1910.95(a) and (b). n1

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n1 29 C.F.R. 1910.95(a) and (b) provides in pertinent part as follows:

(a) Protection against the effects of noise exposure shall be provided when the sound levels exceed those shown in Table G-16 when measured on the A scale of a standard sound level meter at slow response.

(b)(1) When employees are subjected to sound exceeding those listed in Table G-16, feasible administrative or engineering controls shall be utilized.   If such controls fail to reduce sound levels within the levels of Table G-16, personal protective equipment shall be provided and used to reduce sound levels within the levels of the table.


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The order directing review asked for submissions on the following issues:

(1) Whether Respondent met requirements of 29 C.F.R. 1910.95(b)(1) as to the utilization of feasible administrative or engineering controls.

  (2) Whether substantial evidence on the record as a whole supports the Secretary's citation.   If so, whether those violations were serious within the purview of section 17(k) of the Act. n2

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n2 Review was also directed on the issues whether the personal protective equipment made available to the employees, when used, effectively reduce the sound levels within the levels of Table G-16 as set forth in 29 C.F.R. 1910.95, and whether Respondent had a continuing effective hearing conservation program.   Complainant properly concedes that the personal protective equipment, including ear plugs, muffs, and Swedish Wool, made available to Respondent's employees, when properly used, does effectively reduce sound levels within permissible limits.   Southern Indiana Gas & Electric Company, O.S.H.R.C. Docket No. 456, BNA 1 O.S.H.R. 1569, CCH Employ.   S. & H. Guide para. 17,347 (Rev. Com'n. March 5, 1974).

As to the other issue there is no allegation in either the citation or complaint that Respondent failed to have a continuing effective hearing conservation program.   The subsection (29 C.F.R. 1910.95(b)(3)) that requires such a program was not specifically alleged to have been violated.   Further, in response to the Judge's pre-trial instructions, the issues to be tried were enumerated by each party: neither party listed as an issue the failure to have a continuing effective hearing conservation program.   There has been no motion, either before or during trial or in the briefs on review, to amend the pleadings so as to allege such a failure.   Accordingly, we do not reach the issue.


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On review, both parties argue that the issue of feasible administrative or engineering controls is not relevant.   We agree.   Respondent (hereinafter "Sun Ship") was not cited for having failed to provide administrative or engineering controls, and the issue was not tried by the parties.   Rather, Sun Ship was alleged to have violated the standard solely on the basis that some of its employees were not wearing personal ear protective equipment while being exposed to excessive noise levels.   The violation   was alleged to be serious on the basis that the exposures would result in serious injuries in that employees would suffer loss of hearing.   These were the issues presented by the parties and decided by Judge Chalk.

In deciding this case Judge Chalk correctly noted that Complainant must show that employees who were without ear protection were exposed to sound levels in excess of the limits prescribed by Table G-16 n3 However, contrary to the decision below Complainant is not required to show that an observed excessive noise level continued uninterrupted for a period specified by the Table and [*4]   preceeding the making of the observation.

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n3 Table G-16 is as follows:

Duration per day, hours

Sound level

dbA slow












1-1 1/2




1 1/2


1 1/4 or less


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A prima facie case may be established on a showing that an employee has been exposed to a specified sound level for more than the period specified for that level in a day.   For example if an unprotected employee is exposed to 110 dbA for more than 30 minutes in a work day regardless of whether the period is continuous or discontinuous a prima facie violation is thereby established.   Moreover, the proofs may be direct, indirect or a combination of the two.

Thus, Complainant may establish a case with monitoring data for the entirety of any of the periods prescribed by Table G-16 so long as the data is of actual employee exposure. Or, Complainant may establish a case with instantaneous monitoring data (grab or spot samples of sound levels) so long as this data is supported by other evidence [*5]   from which it may be reasonably inferred that employees were exposed to excessive sound levels as defined by Table G-16.

The case before us is one wherein Complainant's representative took grab or spot samples.   Each sample was of approximately 30 seconds duration and was taken in the vicinity of the ears of employees who were not wearing personal ear protection equipment.   We turn now to the four instances alleged in combination as constituting a single serious violation of the Act.

Item 1 -- The Boiler Shop

By this item it was alleged that a pneumatic chipping tool operation was being performed in the boiler shop, and one employee not wearing ear protection was exposed to 117 dbA(s) for a period of 2 hours and 20 minutes.

The facts are that an employee, Wenchak, had been at work for 1 - 1/2 to 2 hours, and had been operating a chipping tool (chipper) for 1 - 1/2 hours prior to the arrival of Complainant's industrial hygenist, Benjamin.   Wenchak was not wearing personal ear protective equipment (Swedish wool) although he had such equipment on his person.   He explained that he had used such   equipment for a number of years but on this occasion had forgotton to use it   [*6]   since it was the first day back on the job after a layoff.   Another chipper was performing a similar operation in Wenchak's area, and this chipper was wearing personal ear protective equipment.   Both chippers had been working for about the same length of time, and the operation was almost continous.

Benjamin took three grab samples of the noise levels in the vicinity of Wenchak's ears. He obtained readings of 116, 117, and 120 dbAs.   The record is silent as to the intervals existing between readings, but as noted above each reading lasted about 30 seconds.

According to Table G-16 an employee may not be exposed in one day to sound levels of 115 dbA and higher for more than 15 minutes. On this record we believe it is reasonable to infer that Wenchak was exposed to impermissible sound levels.   We note that during the entire 1 - 1/2 hour period at least one chipping tool was in operation and both were in operation together for most of the period.   Secondly, we note that all of the samples exceeded 115 dbA.

Under these circumstances, the reasonable inference is that Wenchak was exposed to 115 dbA sound levels for more than 15 minutes. Accordingly, Complainant established a prima facie [*7]   violation which Sun Ship has not rebutted on the record.

We turn now to the question of whether the violation was serious.   The record is replete with evidence that exposure of the kind experienced by Wenchak will produce hearing impairment if the exposure is had over a normal working lifetime.   And it can be said that such loss constitutes a serious injury within the meaning of section 17(k).

  However, the evidence of record is that Wenchak's exposure was for 1 - 1/2 hours, that he normally wore personal ear protective equipment, and that he applied such equipment during the course of the inspection. There is no evidence from which we can conclude that Wenchak's exposure would likely result in hearing loss or impairment.   Accordingly, the evidence only establishes an other than serious violation.

Item 2 -- Double Head Grinder

On review, Complainant states that he has failed to establish duration of exposure. We agree, and the Judge's decision to vacate will be affirmed.

Item 3 -- Fabrication Shop

A welder, Long, was operating a chipper to rough off tacks on hull plates when Benjamin arrived in the fabrication shop. Long was not wearing ear protective equipment,   [*8]   and Benjamin took two grab samples at his ear. Readings of 112 and 113 dbA were obtained.   Benjamin then backed off for the purpose of obtaining background noise readings, and he measured 104 to 106 dbA.

Unlike the situation in the boiler shop, Long did not know how long he had been operating the chipper when Benjamin took his samples.   However, on the day of the inspection Long roughed off 180 lineal feet of plate and spent the rest of his time performing welding duties.   One witness estimated that the chipper was used for a total of five minutes. Long guessed that it would take 5-10 minutes to rough off 40 lineal feet of plate. Thus his estimate   of the period of use of the chipper ranges from 22 1/2 to 45 minutes.

If it is assumed that a single chipper produces noise levels of 112-113 dbA, then the permissible exposure periods are about 22 minutes at 112 dbA and 18 minutes at 113 dbA. n4 Complainant had the burden of proving both the assumption and either exposure period.   As to the assumption it is possible that the levels could have varied.   More important, however, is the fact that even Long had to guess as to the period of operation of the chipper. A violation [*9]   predicated on his guess would necessarily assume the accuracy of the guess.   Even then the question would be close if his 5 minute estimate was used.   Under the circumstances we think any inferences drawn from this evidence would be in the nature of pure speculation.   Accordingly, we conclude that Complainmant has failed to carry his burden of proof, and this item of the citation must be vacated.   Armor Elevator Company, Inc.,   S. & H. Guide para. 16,958 (Rev. Com'n., 1973).

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n4 Values other than those expressly prescribed by Table G-16 may be obtained by plotting the values given in the Table.

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Item 4 -- Welders

Employees Anderson and Mirano were welding just off a walkway in two wing tanks in the lower cargo section of a ship.   There was an unnamed employee "topside" chipping intermittently.   Employee April was chipping in an adjacent compartment.   Anderson and Mirano were approximately 75 feet apart widthwise in the cargo section.   Though not [*10]   clear from the record it appears that both welders were from 20 to 40 feet removed from both chippers. Benjamin took grab samples at the ear of both named employees getting readings of 103 and 104 dbA.   Neither employee was wearing ear protection.   At the time the 103 and 104 readings were obtained, chipping was taking place.   Benjamin also took grab samples while standing on the walkway when the chipping machines were silent.   He obtained readings of 94 to 96 dbA.   It was not established how long Anderson, Mirano or April had worked, prior to the sampling, at the station where Benjamin found them.

The trial Judge found that the above facts do not establish a violation.   We agree.   This item suffers from the same deficiency of proof as does item 3.   There is no direct evidence of impermissible duration of exposure, and unlike item, 1, but like item 3, there is an insufficient record upon which we can legitimately infer such exposure. Here there is no evidence to establish the whereabouts of either welder except at the time of Benjamin's testing in relation to sources of noise and therefore noise levels.   To sustain his burden of proof, Complainant had to establish that the two   [*11]   welders were exposed to 103-104 dbA in excess of 1 hour and 10 minutes or the 94/96 dbA for approximately 4 hours.   We will not infer such duration or exposure where there is no evidence to support such an inference.

Item 1 -- Penalty

For the alleged serious violation of 29 C.F.R. 1910.95(a) and (b) Complainant proposed a civil poenalty of $600.   As hereinbefore noted, we find   Sun Ship in non-serious violation of the cited standard as to item 1.   The gravity of the violation is low on this record, and the violation was abated immediately.   Respondent's business is large.   We have no reason to doubt Respondent's good faith, and it does not have an adverse prior history under the Act.   Considering all the above, we do not believe it appropriate to assess a penalty.

For the reasons stated the Judge's order is modified to find a non-serious violation of 29 C.F.R. 1910.95(a) and (b) as to item 1.   No penalty is assessed.   The Judge's order, as amended, is affirmed, and it is so ORDERED




  CLEARY, COMMISSIONER, concurring in part and dissenting in part: I agree with Commissioner Van Namee that the Secretary proved only a non-serious [*12]   violation of the Act by respondent's non-compliance with respect to item 1 (the boiler shop).   I also concur with the vacation of item 2 (double head grinder) inasmuch as the Secretary has moved to withdraw it, and with the vacation of item 3 (fabrication shop).

Concerning item 4, Commissioner Van Namee states that: "[i]t was not established how long Anderson [a welder], . . . or April [a chipper], had worked prior to the sampling at the station where Benjamin found them," and that "there is no evidence to establish the whereabouts of [Anderson] except at the time of Benjamin's testing in relation to sources of noise and therefore noise levels."

I must disagree.   On direct examination, employee Anderson testified as follows:

  Q.   On the day of the inspection where were you working with relation to Mr. April?

A.   Well, I couldn't say where Mr. April was working.   I was working in [the] Four Port [tank] on [the number] Six Way on the day in question.

April's position was also fixed in his testimony:

Q.   And on the day of the inspection, where were you working?

A.   In Three Center [tank] on [the number] Six Way.

Thus, both workers' positions in the ship were established.   [*13]   April further testified that he chipped for six and one half hours on the day of the inspection. When chipping occurred, the noise level at Anderson's ear reached 103-104 dbA; background noise without chipping reached 94-96 dbA.   Permissible duration of exposure to 94 dbA is four and one half hours; to 103 dBA, one and one quarter hours. n5

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n5 These numbers were arrived at through graphical interpolation on the following.

[SEE ILLUSTRATION IN ORIGINAL] My colleague, Commissioner Van Namee uses interpolated values in his opinion, a practice in which I join and which I approve.   This is a common mathematical process for finding intermediate values that are tabulated.

Without interpolation of course the standard's usefulness in assuring healthful working conditions with respect to noise exposure could be impaired in some cases.   An excessively literal reading of the table therefore seems not likely intended by the draftsmen.   For example, suppose an employee had been exposed to 91 dBA for 6 hours and 96 dBA for 1 hour.   Without interpolation, we would have to use the next lowest listed sound levels, and there would be no violation.

6/8 + 1/4 = 1.

But with interpolation, a violation would be uncovered:

6/7 + 1 / 3 1/7 > 1.

Moreover, the Secretary, in his brief, has interpreted the standard as allowing the use of interpolation. The Secretary's interpretation is entitled to some deference.   Brennan v. Southern Contractors Service, 492 F.2d 498 (5th Cir. 1974), and it is in order here.

Furthermore, this case illustrates the difficulty of enforcement of the Act that would ensue without interpolation. The 94-96 dBA readings would have to be treated as if they indicated 92 dBA, the next lowest level; (using 95 dBA as an "average" would be unsupported by the evidence).   The 103-104 readings would have to be treated as if they were 102 dBA, the next lowest level.   In this case, of course, a violation would still be found, since the permissable exposure to 102 dBA (1-1/2 hours) and 92 dBA (6 hours) were nevertheless exceeded.

Finally, without interpolation, readings would be "discounted" to values lower than the actual readings indicated.   With interpolation, we need not engage in such unnecessary fiction.


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  In addition, Anderson's day-long exposure to the background noise alone while in the Four Port tank exceeded four and one half hours.   On this basis as well, a violation is established.

Moreover, use of the cumulation formula set out below Table 16 n6 compels the finding of a violation.   Thus, a violation is established if respondent's employee is exposed to 94 dBA and 103 dBA for one hour at each level.

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n6 "When the daily noise exposure is composed of two or more periods of noise exposure of different levels, their combined effect should be considered, rather than the individual effect of each.   If the sum of the following fractions: C1/T1 + . . . Cn/Tn exceeds unity, then, the mixed exposure should be considered to exceed the limit value.   Cn indicates the total time of exposure at a specified noise level, and Tn indicates the total time of exposure permitted at that level. . . ."

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Using the formula, C1/T1 + C2/T2 + . . .   [*15]   + Cn/Tn > 1, to find a violation, a one hour exposure to each level exceeds unity.   Substituting values:

1 / 4 1/2 + 1 / 1 1/4 = 46/45>1.

A violation is established even if the background noise and chipping lasted only one hour each. Therefore, I do not join with my colleague's statement that the Secretary "had to establish that the two welders were exposed to 103-104 dBA in excess of one hour and ten minutes or the 94/96 dBA for approximately four hours." The cumulation formula allows us to find a violation even when such conditions are not fulfilled.   The record of course reveals that respondent's employees spent the entire day in the number three and four tanks.   Therefore I would find that the Secretary has   satisfied his burden of showing, by a preponderance of the evidence, employee exposure to excessive sound levels.

Inasmuch as Anderson never wore effective ear protection n7 before the date of inspection, the likelihood of substantial hearing damage is apparent.   Respondent's contention that the Secretary must show actual or probable hearing damage resulting from actual long-term exposure, if adopted, would impose an excessive and undue burden upon the   [*16]   Secretary.   Instead, I would infer a substantial probability of hearing loss from evidence that lack of effective ear protection occurred on a regular, non-intermittent basis. n8 This clearly distinguishes item 1, since it appears there that the employee's failure to use ear protection was inconsequential.

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n7 Anderson's personal "protective" equipment consisted of ordinary cotton or paper towels that expert testimony established as clearly ineffective, and I would so find.

n8 It is possible that hearing loss could occur after even one exposure to high noise levels.   In such a case, the above would, of course, not apply, and the Commission need not inquire into the regular use vel non of protective devices.

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MORAN, CHAIRMAN, dissenting: Judge Chalk decided this case correctly and I would affirm his decision in all respects.

Since the two individual opinions which precede this one are in disagreement on the nature of the burden of proof for establishing non-compliance with the industrial noise limitation regulation,   [*17]   I take note of the fact that this decision states no rule on that matter.

[The Judge's decision referred to herein follows]

  CHALK, JUDGE, OSAHRC: In a Citation for Serious Violation dated November 22, 1971, Respondent, an employer engaged in a business affecting the commerce of the United States, was charged with four specific noise level violations of 29 CFR 1910.95(a) and (b), each relating separately to a specific individual, or, in one case, to a group of individuals, as follows:


1) Pneumatic chipping tool operation on low bay condenser in the Boiler Shop. Two men exposed, one man not wearing ear protection.   Exposure time -- 2 hours, 20 minutes (10 minute rest period).   A scale=117 dBA(s).   Hearing zone of operator.

2) Doublehead grinder operator within 15 feet of above location.   A scale=108 dBA(s).   No ear protection being worn.   Possible 2 hour/day exposure depending on work load.

3) Fabrication Shop -- Chipper using a pneumatic actuated chisel to cut off tack welds on 3/4-inch hull plate. A scale=112-113 dBA(s).   Capability for 8 plates per day -- possible 40-minute exposure during 8-hour shift.   No ear protection worn.

4) Wing   [*18]   Tank (Lower Cargo Section) -- Welder's locations.   Background noise without chippers. A scale=94 dBA(s).   With chippers=103 dBA(s).   Twelve employees intermittently exposed, possible 8-hour duration. Hearing zone of operators.   No ear protection noted on welders.

A lump-sum penalty of $600.00 was proposed by the Secretary for the four alleged violations.

29 CFR 1910.95 is entitled "Occupational noise exposure" and provides in substance that employers will furnish exposed employees suitable personal ear protective equipment when their exposure exceeds specified time limits at specified sound levels, as set forth in the following table:  




Sound level

per day,

dBA slow



















1/4 or less



The "dBA" readings reflected in this table refer to decibels on the A scale of a standard sound level meter at slow response.

The inspection of Respondent's workplace in Chester, Pennsylvania, on October 14, 1971, wherein a daily average of thirty-five hundred workers are employed, was conducted by a Labor Department industrial hygienist (hereafter [*19]   referred to as inspector)., accompanied by Respondent's safety director and another employee who also served as president of Local 802, Boiler Makers Union.   As a result of the inspection, the Citation was issued, and was duly contested by Respondent.

Because of the length and complexity of the record, the evidence introduced by both parties will be summarized by item number and thus by corresponding location.   Because of the result I reach, there is no need to summarize either the mass of expert testimony adduced or the somewhat controverted evidence as to whether Respondent provided and enforced an appropriate hearing conservation   program for its employees, except as may otherwise be indicated herein.


The inspector, using a properly calibrated sound level meter, took three readings at about thirty second intervals close to the ear of one Alex Wenchak who was operating a pneumatic chipping gun in the boiler shop cutting holes in a steel condenser.   These readings reflected sound levels of 116, 117, and 120 decibels on the "A" scale, respectively.   Another employee was also operating an identical chipping gun on the same condenser at the time.   Also [*20]   contributing to the noise was a nearby double head grinder that was running when the inspecting party first arrived in the shop, apparently because its previous user had forgotten to turn it off.   At some unknown point while the readings were being taken, a "chipper" started using it to sharpen his tools.

Although the "chipper" working with Mr. Wenchak was wearing ear protective equipment, Mr. Wenchak was not.   When the inspector mentioned this to Mr. Wenchak, Mr. Wenchak immediately removed a cotton-like material called "Quiet Down," protective equipment that complies with the standard, from his pocket and placed it in his ears, explaining that he had been furnished the same by Respondent and told to use it, but had forgotten to do so that day.   The inspector considered Mr. Wenchak's failure to wear the protective equipment an "oversight" on his part.

Mr. Wenchak testified that he "just forgot" to use the Quist Down that day because it was his first day back on the job after a lay-off for a period of time   and he was "excited" because he was working "in a different shop." Before the inspector arrived, he had been operating his chipping gun "off and on" for an hour and   [*21]   a half to two hours "or more," with a few stops during this time.   He explained that when the gun was not touching the condenser, it made no noise, that discounting the time his gun was not being operated, he had been "cutting" for more than an hour, and that when his gun was not running the other "chipper's" gun was.   Mr. Wenchak also testified that his foreman told him to wear the ear protective equipment and that he had complied with this requirement "all the time" during the four years he had been working for Respondent.

Item 2 -- Double Head Grinder

The inspector took readings close to the ear of an unidentified employee who was using a double head grinder at a location about fifteen feet from where Mr. Wenchak was operating his chipping gun. He obtained a reading of 118 decibels when the employee was using the grinding wheel and 108 decibels when he was not.   The inspector noted that the employee was not wearing ear protective equipment, but he did not obtain the employee's name and was unable to say that the employee was so exposed for two hours, as charged.   The grinding machine is available for the use of any employee who may need to sharpen a tool or other instrument.   [*22]  

The safety director testified that the unidentified employee appeared at the grinder only shortly before the inspector took the readings and that he remained there no more than thirty seconds and   departed.   The union representative corroborated the fact that the employee had appeared at the grinder to sharpen a tool immediately before the readings were taken.   Also, according to this witness, the grinder was running before this employee approached it, presumably because the previous user of the grinder had neglected to turn it off.

Item 3 -- Fabrication Shop

Proceeding next to the fabrication shop, the inspector took readings of 112 and 113 decibels near the ear of one Meredith Long who was operating a chipping gun "roughing off tacks" on a hull plate. Other men were working or "mulling around" in this area.   By stepping back about fifteen feet from Mr. Long, the inspector got readings of 104 to 106 decibels. Mr. Long was not wearing any ear protective equipment.   The inspector noted that "other equipment," such as an air blower, which "definitely" added to the noise level, was contributing to the noise level in the area.   According to him, "there were many noises created [*23]   in the shop." He did not know the duration of Mr. Long's exposure.

Mr. Long testified that he was not wearing ear protective equipment when the inspector was there and that he had not worn any in the past.   Since the day of the inspection, however, Respondent issued an order directing all persons working within fifty feet of a "chipper" to wear the same.   Mr. Long started work that day at 7:45 a.m. and the inspector arrived at his workplace at 11:20 a.m. He also stated that he had only been at "that particular job there" for three minutes before the inspector arrived on the scene.

The union representative testified that the other   persons working nearby were "chippers" to Mr. Long's immediate left and "fitters" on both sides of him.

Item 4 -- Wing Tank, Lower Cargo Section

Inside of a ship, the inspector took readings near the ears of four welders located in the lower cargo section who were working some thirty feet away from a "chipper" who was in turn working "topside." There may have been more than one "chipper," but he saw only one.   When the "chipper" was not working, he obtained readings of 93 and 94 decibels, that he "believe[d]" could have been produced solely   [*24]   by the welding operations going on, at the time, although he indicated that some other source or sources, unidentifed, could have been contributors.   When the "chipper" was working, he obtained readings of 103 and 104 decibels. He did not obtain any of the welders' names, but stated that none of them wore ear protective equipment.   Thereafter, he qualified this statement by testifying that he knew that four welders were not wearing such equipment.   He did not ask any of them if they had such equipment on their persons.   He was told that welders "could be exposed to a possible eight-hour duration, and that's why it was written, you know, in this fashion," apparently referring to allegations in the Citation.   He then stated the opinion that the "chipper" in question "can work intermittently . . . but it would be a continuous din all day long."

The "chipper" in question, who was wearing proper ear protective equipment, testified that his work requires him to operate his chipping gun six and one half to seven hours a day.

  Two of the welders involved appeared as witnesses for Respondent.   One did not remember whether he was wearing ear protective equipment, but if he was, it [*25]   was only absorbent cotton or a piece of paper towel.   The other admitted that he was not wearing anything.   One of them stated that he "would say" that he worked a full eight-hour day that day, that he "quess[ed]" he heard the "chipper," and that the noise was "normal" on that occasion.

The Secretary must support his allegations in any case with substantial evidence, that is with evidence that affords a substantial basis of fact from which a fact in issue can reasonably be inferred (Administrative Procedure Act, 5 USCA 556(d); NLRB v. Columbian Enameling and Stamping Company, 306 US 292, 59 S. Ct. 501, 83 L.Ed. 600 (1939); See Consolidated Edison Company v. NLRB, 305 US 197, 59 S.Ct. 206, 83 L.Ed. 126 (1938)). He may not support any part of his case on suspicion, conjecture, or speculation ( Troutman v. Mutual Life Insurance Co., 125 F2d 769 (6th Cir; 1942)).

Because of the very nature of the violation, the Secretary's burden of proof in noise violation cases is vastly different and usually more difficult than most other violations where evidence of the violation is patently before the investigation official at the moment he observer the condition.   Instead,   [*26]   what the investigating official sees before him in a noise violation case is only an indication that a violation may have occurred, when he was not present, during a period of time immediately preceding the time of his inspection. Thus, the Secretary must necessarily adduce evidence in these cases that the exact condition that his investigating official observed existed uninterrupted for that period of   time prior to the investigating official's observation, and, of course, that the employee or employees involved were subjected to it throughout that period of time without appropriate ear protective equipment.

I speak in terms of the exact condition -- the sound level -- existing for the required period of time in the past, for in the normal course of human events, I seriously doubt that an employer would be so naive as to allow the observed condition to continue to exist in the investigating official's presence so that he eventually becomes a witness to the violation itself.   I also temper my use of the word "uninterrupted" with the word "substantially," for I incline to the belief that insubstantial interruptions in the continuity of the condition do not render the condition [*27]   any less a violation.

The Secretary's burden, in my judgment, becomes exceedingly more difficult in some noise violation cases as the number of noise sources contributing to the observed noise level increases, for all contributing sources must be shown to have so contributed throughout the period in question and usually must be identified.

Finally, extreme care must be exercised in evaluating every aspect of the evidence offered in support of this violation, for its complexity, from the standpoint of proof, lends readily to a subconscious lapse into conjecture.

Cast in the light of these principles, the evidence in this case, or, more appropriately, the lack of it, convinces me that the Secretary has not sustained his burden of proof as to any of the alleged four violations, for the reasons that follow.

  Item 1 -- Boiler Shop

The three readings in the boiler shop were taken at a time when two chipping guns were being operated.   While it was also established that the grinder nearby was running at this time, it was not established that the readings, or any of them, were taken when the grinder was being used to sharpen tools, or, for that matter, whether the noise generated [*28]   by the use of the grinder increased the sound level over that generated by the grinder when it was running but was not being used. n1 This, perhaps, may account in part for the substantial variance between the three readings taken closely together.   The evidence, moreover, is otherwise deficient, for it leaves unanswered whether the other "chipper" was operating his chipping gun at any time prior to the inspection, other than those times when Mr. Wenchak was not operating his chipping gun, whether the grinder was running for any particular period prior to the inspection, and, if so, whether it was being used to sharpen tools, and what the noise levels were when only one chipping gun was being operated without the grinder running, or with it running, or with it being used to sharpen tools.   Finally, Mr. Wenchak's testimony does not even establish with the required degree of certainty that he operated his chipping gun without substantial interruption for any   specific period of time prior to the inspection. In sum, the Secretary established nothing more than sound level readings of from 115 to 120 decibels at the time of the inspection; hence his allegation is not supported [*29]   factually or legally by substantial evidence of record.

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n1 I have not overlooked the testimony of the inspector that when he took two readings near the ear of the employee using the grinder, he obtained one reading of 108 decibels when the employee was not using the grinder and another reading of 118 decibels when he was using the grinder. As to the 108 decibel reading, the inspector testified only that he "believe[d]" the grinder was still running.

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There is yet another reason in my judgment why this allegation cannot be upheld.   Even were I to conclude on this record that Respondent's enforcement program pertaining to hearing conservation left something to be desired, as the testimony of some of the witnesses seemed to infer, Mr. Wenchak had been furnished proper ear protective equipment by Respondent, had been told to use it, and had used it "all the time" during his employment there for about four years.   Under these unusual circumstances, and especially in light of the fact that it would be virtually impossible [*30]   for Respondent to "police" all of its employees (thirty-five hundred daily average), Respondent cannot be held responsible for Mr. Wenchak's "oversight" on this one isolated occasion (see Secretary of Labor v. Standard Glass Company, Inc., Docket Number 259, July 29, 1972; Cf Secretary of Labor v. Pacific Food Products Company, Docket Number 158, April 6, 1972.)

Item 2 -- Double Head Grinder

The allegation pertaining to the employee using the double head grinder requires but little discussion, for the Secretary was unable to establish by substantial evidence that the employee remained at the grinder for any more than a few minutes, as established by the testimony of Respondent's safety director and otherwise supported by the testimony   of the union representative. Thus, this allegation is not factually and legally established by substantial evidence.

Item 3 -- Fabrication Shop

Not unlike Item 1, the boiler shop allegation, multiple or "many" noise sources were noted by the inspector but not identified, other than an air blower that was running at the time he took the readings.   While he admitted that the air blower alone "definitely" added to the noise level,   [*31]   he also admitted that he did not take a reading to determine the "sound level reading from the blower." The union representative testified that other "chippers" and some "fitters" were also working nearby.   Although Mr. Long testified that he had been at work some three and one half hours before the inspector took the readings near his ear, no evidence was adduced to show any particular period of time that he was continually present and subjected to any particular sound level for the period of time required.   In fact, he made one statement that raises the inference that he had only been at "that particular job there," presumably where the readings were taken, for only three minutes before the inspector arrived. Also left unanswered on this record is whether the other noise sources, the blower and the others unidentified by the inspector, and the "chippers" and "fitters" noted by the union representative, were contributing to the noise level for any particular time, if at all, prior to the time the readings were taken, or what the sound level reading was without some of any of these sources contributing to the din.   This allegation, therefore, is not factually or legally supported [*32]   by substantial evidence.

  Item 4 -- Wing Tank Lower Cargo Section

The inspector's testimony, alone, raises substantial questions as to the sufficiency of the Secretary's case, for the inspector equivocated on the number of welders involved in the allegation and he admitted that the allegation was drafted to reflect a "possible" eight-hour exposure because he had been informed that welders could be "exposed to a possible eight-hour duration, and that is why it was written, you know, in this fashion." In any event, there was at least one employee nearby who was operating a chipping gun intermittently.   When this employee was using the gun, the readings varied between 103 and 104 decibels; when he was not operating the gun, the readings varied between 93 and 94 decibels. The welding operations apparently also contributed substantially to the noise level, but the extent or duration is unknown.   In sum, the evidence presented as a whole fails to establish the exposure of any person not wearing ear protective equipment to any particular sound level for any sustained period of time. Accordingly, the allegation is not factually or legally supported by substantial evidence.

The [*33]   record as a whole supports the asserted jurisdiction of this Commission over the cause and no jurisdictional issue was raised during any of the proceedings.

The Citation and proposed penalty are vacated.

It is so ORDERED.