OSHRC Docket No. 7801

Occupational Safety and Health Review Commission

April 11, 1977


Before BARNAKO, Chairman; MORAN and CLEARY, Commissioners.


Baruch A. Fellner, Office of the Solicitor, USDOL

Francis V. LaRuffa, Reg. Sol., USDOL

P. E. Gammons, Republic Steel Corp., for the employer




BARNAKO, Chairman:

This case presents the issue of whether Judge Robert P. Weil properly vacated a citation issued under the Occupational Safety and Health Act of 1970 (29 U.S.C. 651 et seq., hereinafter "the Act") which alleged noncompliance with 29 C.F.R. 1910.94(d)(4). n1 Judge Weil determined, among other things, that the cited standard's ventilation provision applies only where the airborne concentration of a hazardous substance exceeds the threshold limit value (hereinafter "TLV") for that substance designated by 29 C.F.R. 1910.1000. n2 For the reasons below, we affirm the Judge's vacation of the citation.

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n1 The cited standard reads in pertinent part as follows:

1910.94 Ventilation

(d) Open surface tanks

(4) Control requirements (i) Control velocities shall conform to Table G-14 in all cases where the flow of air past the breathing or working zone of the operator and into the hoods is undisturbed by local environmental conditions, such as open windows, wall fans, unit heaters, or moving machinery.

n2 Judge Weil referred to that section as 1910.93. We note that section 1910.93 was redesignated 1910.1000 at 40 F.R. 23072 (May 28, 1975).


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The facts surrounding the alleged violation are largely undisputed. Respondent was engaged in the processing of steel tubing during which the tubing was treated in a series of open-surface tanks. The open-surface tank in question n3 contained 2500 gallons of a sodium hydroxide solution in which the tubing was cleaned. The tank operator stood approximately two to three inches from the tank. The parties agreed that the tank operator was exposed to only five percent of the TLV for airborne concentrations of sodium hydroxide as provided in 1910.1000.

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n3 Respondent was cited for violations at three tanks, all of which the Judge vacated. On review, the Secretary admits that he did not prove violations as to two of the tanks; the Clepo caustic tank and the sulphuric acid tank. Thus, only the sodium hydroxide caustic tank is at issue.

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The tank was equipped with a lateral exhaust system and the flow of air around the tank was not disturbed [*3] by local environmental conditions such as open windows or fans. The tank operation was classified under 1910.94(d)(2) as a C-2 operation. n4 The parties stipulated that, assuming the applicability of 1910.94 where the concentration of airborne sodium hydroxide does not exceed the TLV, the minimum ventilation rate for the sodium hydroxide tank set by Tables G-14 and G-15 of 1910.94 is 10,800 cubic feet per minute. It was agreed that the ventilation rate at the tank was below that level.

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n4 Section 1910.94(d)(2) provides that the class of open-surface tank operations is to be determined by two factors: a hazard potential designated by the letters A through D, and the rate of gas, vapor, or mist evolution designated by the numbers 1 through 4. For the operation in question, the Secretary calculated the hazard potential based on Table G-12 to be class C because the TLV for sodium hydroxide mist is 2 milligrams per cubic meter. The Secretary calculated the rate of gas, vapor, or mist evolution based on Table G-13 to be class 2 because the operating temperature of the substance was 160 degrees. Respondent does not dispute the classification.


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The industrial hygientist who testified for the Secretary stated that the concentration of sodium hydroxide in the air, although below the TLV, presented potential hazards to employees in the area. He identified the potential hazards as corrosive action of employees' respiratory systems, dermatitis due to contact or condensation of sodium hydroxide on the skin, and slippery conditions due to condensation of vapors on walking surfaces. He did not testify that the concentration of sodium hydroxide created a fire or explosion hazard, or a hazard from decreased visibility or increased humidity.

For these reasons, Respondent was issued a citation alleging a nonserious violation of 29 C.F.R. 1910.94(d)(4) in that the control velocity at the cited open-surface tank did not conform to the velocity rate set out in Table G-14. A $55 penalty was proposed.

Judge Weil granted Respondent's motion to dismiss the case at the end of the Secretary's case-in-chief, thereby vacating the citation. He adopted Respondent's argument that the ventilation provision in 1910.94(d)(4) is not an absolute mandate but rather [*5] applies only where the TLV levels specified by 1910.1000 are exceeded. In this regard, he read 1910.94(d)(4) as being limited by 1910.94(d)(3), which states that the purpose of the ventilation provision is to control potential exposures to workers as defined in 1910.94(d)(2)(iii). The Judge interpreted 1910.94(d)(2)(iii) as defining potential exposures to mean the TLV levels set by 1910.1000. He was further persuaded to his interpretation because section 1910.94(d)(4) speaks in terms of the "flow of air past the breathing or working zone of the operator." Accordingly, since the concentration of sodium hydroxide in the working zone of the tank operator was only five percent of the TLV for that substance, the Judge found that additional ventilation was not needed. n5

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n5 The Judge also referred to Judge Worcester's decision in Omni-Metal Castings, Inc., 19 OSAHRC 412, BNA 3 OSHC 1391, CCH OSHD para. 19,869 (1975), wherein Judge Worcester held that 1910.94(b)(3)(ii) was not violated unless air contaminant levels exceeded the TLV provided in 1910.1000. The Judge noted that the decision was affirmed by a divided Commission. On review, the Secretary seeks to distinguish Omni-Metal, whereas Respondent argues that the case supports its position. Inasmuch as cases decided by an equally divided Commission do not represent precedent as was said in Omni-Metal we decline to consider or rely on the case.


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On review, the Secretary objects to the Judge's conclusion that TLV levels must be exceeded before ventilation pursuant to 1910.94(d)(4) becomes necessary. He argues that such an interpretation renders 1910.94(d)(4) redundant to 1910.1000 and that, if 1910.94(d) had been intended to apply only where TLV levels were exceeded, this requirement would have been specifically set out in the standard. The Secretary urges that the ventilation provision in 1910.94(d)(4) applies independently of the TLV levels. He contends that the ventilation provision was meant to protect employees against hazards in addition to the breathing of toxic materials. In this regard, the notes that the ventilation rates in Table G-14 are calculated from the classifications of toxic materials as determined by 1910.94(d)(2) and that these classifications take into account not only the TLV, but also the rate of gas, vapor, or mist evolution. The Secretary also points to the source standard for 1910.94(d), ANSI Z9.1-1971, which lists as its purposes the prevention of emissions of a substance in quantities tending to injure health, [*7] condense upon workroom surfaces, or accumulate in the air so as to reduce visibility or increase humidity.

Respondent argues in favor of the Judge's interpretation of the standard. In support of this interpretation, it maintains that the source standard, ANSI Z9.1-1971, made the ventilation provision expressly contingent on a showing that the ventilation was insufficient to insure that employees were not exposed to excessive levels of a toxic substance, and stated that the escape of small amounts of a toxic substance was acceptable. It further contends that it is clear, when 1910.94(d)(4) is read in context with other provisions of the same section, that the standard's applicability is conditioned on the existence of concentrations of toxic substances in excess of the TLV levels.

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n6 Respondent also argues that, if 1910.94(d)(4) is interpreted in the way urged by the Secretary, the standard was improperly promulgated under section 6(a) of the Act since the operational effect of the occupational safety and health standard differs from the underlying ANSI standard. Our disposition of the case makes it unnecessary to pass on this argument.


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We have carefully considered the Judge's decision and the parties' arguments and have reviewed the cited standard in context with other provisions in the same section. We conclude that the ventilation provision of 1910.94(d)(4) applies only where the Secretary proves that the concentration of a toxic substance in the air exceeds the TLV level or that there is a fire or explosion hazard from the concentration of the toxic substance in the air.

The cited standard is part of section 1910.94(d) which deals with ventilation and other means of reducing to non-hazardous levels concentrations of air contaminants around open-surface tanks. It sets out control velocities which are based upon the classification of the toxic substance involved. However, it is appropriate to read the cited section in conjunction with 1910.94(d)(3), which sets out the circumstances under which ventilation is to be used. Section 1910.94(d)(3) is entitled "Ventilation" and provides that:

Where ventilation is used to control potential exposures to workers as defined in sub-paragraph (2)(iii) of this paragraph, it shall be adequate [*9] to reduce the concentration of the air contaminant to the degree that a hazard to the worker does not exist.

Section 1910.94(d)(2)(iii) defines hazard potential as the "hazard associated with the substance contained in the tank because of the toxic, flammable, or explosive nature of the vapor, gas, or mist produced therefrom." Section 1910.94(d)(2)(iii) provides that the toxic hazard shall be determined from the TLV concentrations in 1910.1000, while 1910.94(d)(2)(iv) states that the flammable and explosive hazard is to be measured in terms of the closed-cup flash point of the substance in the tank. Thus, we conclude that it is evident by reading 1910.94(d)(3) and (4) together that the control velocities set out in 1910.94(d)(4) were meant to be applicable only where there exists a toxic hazard due to airborne levels of a substance in excess of the TLV or a fire or explosion hazard as determined by the flashpoint of the substance. Cf. Bethlehem Fabricators, Inc., 76 OSAHRC 62/C2, BNA 4 OSHC 1289, CCH OSHD para. 20,782 (1976).

We are not persuaded to a contrary interpretation of the ventilation provision by the Secretary's argument that the purpose for the underlying ANSI [*10] standard is very broad. The cited standard was originally published as a national consensus standard, ANSI Z9.1-1971, entitled "Practices for Ventilation and Operation of Open-Surface Tanks." The purpose of the entire ANSI standard as set out in section 1.2 is:

. . . to prevent the emission into the workroom atmosphere of gas, vapor, or mist from open-surface tank operations in quantities tending to:

(1) Injure the health

(2) Condense upon floors, ceilings, or walls of any workroom to produce an unsanitary or unsafe condition

(3) Accumulate in the air in a manner which will significantly reduce visibility or objectionably increase humidity.

These rules also are intended to prevent the accumulation of explosive concentrations of gases or vapors in any duct, hood, booth, or enclosure; and to protect the operator from splash or other contact with liquids injurious to his health.

The Secretary contends that this statement of purpose indicates that the ventilation requirement contained in the ANSI standard was designed to prevent not only toxic hazards, but also condensation and slipping hazards. However, the Secretary's argument disregards the fact that sections of the ANSI standard [*11] other than the section dealing with ventilation are specifically directed at such hazards. For example, section 9 deals generally with personal protective equipment designed to prevent liquid and mist from irritating an employee's skin, and section 11.1 requires that floors and platforms around tanks be prevented from becoming slippery both by their type of construction and by frequent flushing. The Secretary's argument also ignores the fact that the ANSI standard contains a specific purpose clause for the ventilation requirement. Section 4 of the ANSI standard states that the purpose for the control velocity requirement is "to reduce the concentration of the air contaminant in the vicinity of the worker below the limits set in accordance with 2.1.1." Section 2.1.1, like 1910.94(d)(2)(iii), sets out the limits as being determined by the toxic, flammable, or explosive nature of the substance. Thus, the ANSI ventilation requirement is of the same scope as the ventilation requirement contained in 1910.94(d)(4).

The secretary also argued that the cited standard would have specified that it applies only when the limits of 1910.1000 have been exceeded had this been the intent of the [*12] drafters. In support of this assertion, he points to two other standards in the same section, 1910.94 (a)(2)(ii) and 1910.94(b)(2), which expressly provide that ventilation is necessary only where TLV levels are exceeded. However, the two standards cited by the Secretary derive from ANSI standards other than the ANSI standard involved here. n7 Moreover, 1910.94(b)(2) has been substantively amended by the Secretary. n8 Since the standards were drafted by different persons at different times, the language of 1910.94(a)(2)(ii) and 1910.94(b)(2) cannot be used as a guide in interpreting 1910.94(d)(4). See 2A Sutherland Statutory Construction 51.01-.03 (4th ed. 1973).

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n7 Section 1910.94(a)(2)(ii) derived from ANSI N2.3-1967, entitled "Immediate and Safe Practices of Abrasive Blasting Operations." Section 1910.94(b)(2) derived from ANSI Z43.1-1966, entitled "Ventilation Control of Grinding, Polishing, and Buffing Operations."

n8 Section 1910.94(b)(2) was amended in 40 Fed. Reg. 24522 (1975).

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The Secretary further [*13] argues that the Judge's interpretation of 1910.94(d)(4) renders that section redundant to 1910.1000. However, as discussed above, the cited standard applies where the Secretary has shown either that the TLV level in 1910.1000 has been exceeded or that there is a fire or explosion hazard. The standard at 1910.1000 does not deal with hazards from fire or explosion. Therefore, our interpretation of 1910.94(d)(4) does not render it redundant.

Applying the provisions of 1910.94(d)(4) to the facts of this case, we conclude that the Secretary has not provided that a hazard within the meaning of 1910.94(d)(3) exists. The TLV level prescribed for sodium hydroxide in 1910.1000 was not exceeded and the Secretary failed to show a fire or explosion hazard. Therefore, additional ventilation in conformance with Tables G-14 and G-15 of 1910.94 was unnecessary.

Accordingly, we vacate the citation which alleged a violation of 1910.94(d)(4) and the penalty proposed therefor. It is so ORDERED.




I dissent from the disposition ordered by my colleagues. Before deciding this important case involving the exposure of employees to sodium hydroxide I would [*14] invite briefs or oral argument on the application of section 1910.94 from qualified amici such as ACGIH, ANSI, and NIOSH (National Institute for Occupational Safety and Health). See 3A C.J.S. 3 at 424, Amicus Curiae. Cf. 1 CFR 305.71.6, Recommendation No. 71-6 of the Administrative Conference of the United States. I would also be receptive to a motion for reconsideration filed by the Secretary indicating that qualified persons or organizations are willing to express their views as amici upon rehearing.

To illustrate the need for briefing of this kind I note that Appendix H to the source standard, ANSI Z9.1 -- 1971, gives sample calculations for minimum ventilation rates that are not triggered by the presence of amounts of airborne contaminants in excess of the threshold limit values. See particularly example H.4, which deals specifically with a sodium hydroxide solution. I would also want to see or hear argument on the Secretary's contention that the ventilation requirement cited here is in part directed against sudden, temporary high levels of airborne contaminants in excess of the TLV. No discussion or refutation of the argument is given in the lead opinion.

If no [*15] standard is found applicable, I would not, in view of the testimony that concentrations of sodium hydroxide not in excess of the TLV may present hazards to employees, dispose of this case until consideration is given to remanding for further proceedings to investigate the possible application of section 5(a)(1). Dunlop v. Uriel G. Ashworth, 538 F.2d 562, 564 (4th Cir. 1976). There is testimony by an expert industrial hygienist pointing out that simply because the TLV was not exceeded does not mean that employees are not subjected to health hazards. The inhalation of even small quantities of sodium hydroxide, a caustic substance, could injure employees, and skin contact could cause skin ulcerations, defattening and emulsifying of skin tissue, burns, holes in the nasal septum and dermatitis.