SECRETARY OF LABOR,
Complainant,

v.

BUNGE CORPORATION,
Respondent.

OIL, CHEMICAL AND ATOMIC WORKERS
INTERNATIONAL UNION AND ITS LOCAL 4-447,

Authorized Employee
Representative
(Docket No. 77-1622).

OSHRC Docket Nos. 77-1622, 78-0838 & 78-2213

DECISION

Before:  BUCKLEY, Chairman; RADER and WALL, Commissioners.

BY THE COMMISSION:

These three consolidated cases are before the Occupational Safety and Health Review Commission under 29 U.S.C. § 661(i), section 12(j) of the Occupational Safety and Health Act of 1970, 29 U.S.C. §§ 651-678 ("the Act").  The Commission is an adjudicatory agency, independent of the Department of Labor and the Occupational Safety and Health Administration ("OSHA").  It was established to resolve disputes arising out of enforcement actions brought by the Secretary of Labor under the Act and has no regulatory functions.  See section 10(c) of the Act, 29 U.S.C. § 659(c).

The three cases have been consolidated on review under Commission Rule 9, 29 C.F.R. § 2200.9. because they involve common parties and common questions of law and fact.  Bunge Corporation ("Bunge") is one of the largest employers within the international grain-handling industry.  As a result of separate inspections of its facilities in Destrehan, Louisiana (Docket No. 77-1622), Galveston, Texas (No. 78-0838), and Osceola, Arkansas (No. 78-2213), Bunge was issued citations alleging violations of the inert or nuisance dust provision of the mineral dust standard at all three of these workplaces.[[1]]  The principal issue on review is whether Administrative Law Judge David G. Oringer erred in vacating these citations on the ground that the inert or nuisance dust provision does not apply to grain dust.  Also on review, in Docket No. 77-1622, are the judge's finding of a violation of the crystalline quartz silica provision of the mineral dust standards[[2]] and the judge's rejection of various procedural defenses.[[3]]

We conclude that neither the inert or nuisance dust provision nor the crystalline quartz silica provision of the mineral dust standard can be applied to regulate employee exposure to grain dust.  On this ground, we vacate each of the citation items on review.  In light of our disposition, we need not reach the procedural issues raised by Bunge in Docket No. 77-1622.

I

A
On March 4, 1977, OSHA began an inspection of Bunge's marine terminal grain elevator at its export port facility in Destrehan, Louisiana.  The citation at issue in Docket No. 77-1622 is based on three air contaminant samples taken by industrial hygienist ("IH") William D. Gribble during that inspection.  Two total dust samples and one respirable dust sample were obtained on April 27.[[4]]  The record establishes, and the parties agree, that the dust collected in these samples was soybean dust, which is a type of grain dust.[[5]]

As a result of its inspection, OSHA issued a citation to Bunge alleging violations of 29 C.F.R. §§ 1910.1000 (c) and (e).  See note 1 supra.  The citation alleged that employees on the fourth floor bin deck and on the shipping gallery were exposed on April 27 to levels of dust that exceeded the mineral dust standard's permissible exposure limits for respirable inert or nuisance dust and for total inert or nuisance dust.[[6]]  The citation further alleged that Bunge failed to determine and implement feasible administrative or engineering controls to reduce those dust levels within permissible limits.

Bunge contested the citation and, in its notice of contest, requested an informal conference with OSHA.  At this conference, Bunge argued that the inert or nuisance dust provision does not apply to the cited conditions because Table Z-3 applies only to mineral dusts, and grain dust is not a mineral dust.  OSHA's representatives indicated that they would take Bunge's contentions under advisement.

Two days later, the Secretary obtained an extension of time to file the complaint in Docket No. 77-1622.  This additional time was used for two purposes--to obtain a laboratory analysis of the three dust samples collected on April 27 and to consult with OSHA's national office on the legal and policy questions raised by Bunge about the scope of the standard.

On June 20, the Bunge air contaminant samples were transmitted from OSHA's New Orleans Area Office to OSHA's testing laboratory in Salt Lake City.  The lab was asked to determine if there was any mineral content in the samples.  Three separate analyses were conducted for this purpose.  On June 27, lab chemist Willard C. Dixon conducted a petrographic analysis, which is essentially no more than a visual examination through a microscope using polarized light.  Dixon saw only organic materials in the three samples.  He saw no particles of crystalline quartz silica or any other mineral.  He reported to his supervisor that his analysis "yielded 100% soybean dust."

On July 8, lab chemist John C. Germ conducted an x-ray diffraction analysis on the samples.  The purpose of this far more sophisticated analysis was to determine whether two specific substances--crystalline quartz silica and cristobalite--were present in the samples.  Based on his analysis, Germ concluded that the samples did not contain cristobalite, but did contain crystalline quartz silica.  The quartz content of each sample was calculated to be less than 5% by weight of all the dust collected.  On July 11, Germ reported his results to the New Orleans Area Office.  Using these results, IH Gribble computed the PEL's for crystalline quartz silica at Bunge's workplace and concluded that these PEL's had been exceeded.[[7]]

During the same time period that the Secretary's representatives were awaiting the results of the laboratory analysis, they also sought to resolve Bunge's contention that the inert or nuisance dust provision of the mineral dust standard does not apply to soybean dust. Initially, this question was presented to OSHA's Regional Office in Dallas, which in turn sought a determination at the national level. Thus, on June 30, a memorandum ("the Holder memo") was sent from an official in the Dallas Regional Office (Holder) to the Office of Field Coordination, a branch of the national OSHA office.  The national office was informed that the question of whether the inert or nuisance dust provision applies to soybean dust had been raised as an issue in a contested case.  It was also informed of a "telephone discussion with Herbert Stokinger of the A.C.G.I.H. TLV Committee who agrees that only those substances containing mineral dust should be cited under Table Z-3."[[8]]

On July 13, the OSHA national office responded by sending a memorandum ("the Wilson-Tice memo") from the Deputy Director for Federal Compliance and State Programs (Wilson) to the Dallas Regional Administrator (Tice). The OSHA Deputy Director concluded that vegetable and animal dusts are not covered under Table Z-3 because they are not "mineral dusts." In particular, the memorandum stated, "[s]oybean dust is a vegetable dust and should not be cited under Table Z-3 of 29 CFR 1910.1000."[[9]]

On July 26, shortly after the New Orleans Area Office had received both lab chemist Germ's report on the quartz content of the three samples and the Wilson-Tice memo on the inapplicability of the cited provision, the Secretary's counsel filed the delayed complaint in Docket No. 77-1622.  The complaint continued to allege noncompliance with the mineral dust standard based on Bunge's failure to implement feasible administrative or engineering controls to reduce excessive dust levels within permissible limits. The complaint also continued to base the charge of excessive dust levels on the three air contaminant samples that were taken on the fourth floor bin deck and the shipping gallery on April 27.  However, the Secretary sought to amend the citation through the complaint to allege that the permissible exposure limits that were exceeded on that date were the PEL's for crystalline quarts silica rather than the PEL's for inert or nuisance dust.  Several weeks later, the Secretary moved to amend his pleadings so as to allege in the alternative noncompliance with the inert or nuisance dust provision, with the crystalline quartz silica provision, or with both provisions of the mineral dust standard.  These motions to amend were granted despite Bunge's objections.  Accordingly, Docket No. 77-1622 proceeded to a hearing on the merits of the two alternative charges.

B
In his decision in Docket No. 77-1622, Judge Oringer vacated the allegation that Bunge violated the inert or nuisance dust provision of the mineral dust standard, but affirmed the alternative allegation that Bunge violated that same standard's crystalline quartz silica provision.  He characterized the violation as nonserious, modified the abatement requirement, and assessed a penalty of $100.

The judge concluded that the inert or nuisance dust provision cannot be applied to regulate employee exposure to grain dust.  In effect, he entered alternate holdings:  (a) the provision does not apply to grain dust because it applies only to mineral dusts or (b) even if grain dust falls within the intended scope of the provision, it cannot be enforced against grain handlers because it does not provide the constitutionally required fair notice that it is applicable.  Concerning the scope of the cited provision, the judge stated:

Patently Table Z-3 prohibits excess exposure of employees to mineral dusts.  All of the substances listed in Table Z-3 are mineral despite the fact that coal may have an organic base.  In this cause the only dusts collected were not mineral dust, but soybean dust, an organic non-inert substance.

On review, the Secretary argues that the judge erred in vacating the inert or nuisance dust allegation.  He argues that the inert or nuisance dust provision should be applied to the cited facts based on the "plain meaning" of the term "nuisance dust," the intent of the drafters as revealed in the history of the provision's development, and the history of the provision's subsequent enforcement as a limitation on both organic and mineral dusts.  In elaborating on his "plain meaning" argument, the Secretary contends that the term "nuisance dust" has generally and consistently been understood, both in the industrial hygiene profession and in the grain-handling industry, to include vegetable as well as mineral dusts.

The Secretary further claims that his enforcement action is consistent with the intent of the ACGIH, the drafters of the inert or nuisance dust TLV's.[[10]]  He asserts that grain dust is biologically inert in that it normally does not result in irreversible health effects such as scarring of the lungs.  He points to provisions of two ACGIH-TLV's pamphlets that suggest that such biologically inert dusts are properly classified as "inert or nuisance dust," regardless of whether they are vegetable or mineral dusts.[[11]] Accordingly, the Secretary reasons, grain dusts are covered by the OSHA mineral dust standard because they are covered under the source standard.

C

We conclude that the mineral dust standard applies only to mineral dusts.  Because it is undisputed that soybean dust is not a mineral dust, neither of the provisions allegedly violated by Bunge applies to the cited conditions.  Accordingly, both of the alternative allegations in Docket No. 77-1622 must be vacated.

In determining the proper interpretation of the mineral dust standard, we look primarily to the language of the standard.  "There is, of course, no more persuasive evidence of the purpose of a statute than the words by which the legislature undertook to give expression to its wishes."  Griffin v. Oceanic Contractors, Inc., 458 U.S. 564, 571 (1982), quoting United States v. American Trucking Associations, 310 U.S. 534, 543 (1940).[[12]]  The standard requires employers to limit the exposure of their employees within permissible exposure limits whenever the employees are exposed "to any material listed in Table Z-3."  Table Z-3 is captioned "Mineral Dusts" and includes, in addition to the PEL's for "inert or nuisance dust" and "crystalline quartz silica," PEL's for two other "polymorphs" of silica (cristobalite and tridymite), for amorphous silica (including natural diatomaceous earth), for five specified silicates, for graphite, and for coal dust.[[13]]  Bunge argues that the table is limited on its face to mineral dust, and that all of the dusts listed in Table Z-3 are mineral dusts.  Although the Secretary attempted to prove that Table Z-3 includes three dusts that are not mineral dusts, the judge found against the Secretary on this factual issue, and we conclude that his finding is supported by the record.[[14]]  We therefore adopt the judge's finding that all of the materials in Table Z-3 are commonly understood to be minerals or mineral dusts.  Moreover, the listing for "inert or nuisance dust" corroborates the firm impression given by the table that organic substances are not included within it because organic matter is not chemically inert.[[15]]  In short, the language of the table, including its title, shows that it is limited to mineral dust.

The Secretary nevertheless urges that the phrase "inert or nuisance dust" should, in contrast with the other dusts regulated by Table Z-3, be interpreted in accordance with a "common understanding" by industrial hygienists and the grain-handling industry that it includes vegetable dusts.  The Secretary apparently would have us ignore the fact that the other provisions of the standard apply only to mineral dusts.  However, we adhere to the principle that the provisions of a standard should be interpreted in the context of the entire standard.  See State Highway Commission of Missouri v. Volpe, 479 F.2d 1099, 1111-1112 (8th Cir. 1973) (a section of a statute should not be read in isolation but rather in the context of the whole act).   See generally, 2A Sutherland Statutory Construction § 46.05 (4th ed. 1984).

In any event, even if we consider the inert or nuisance dust provision in isolation, we are not convinced that the term "inert or nuisance dust" has a special meaning that is commonly understood within the industrial hygiene profession and the grain-handling industry.  The Secretary's assertion of a common understanding in the industrial hygiene profession is contradicted by the record evidence.  IH Gribble and Dr. Richard testified in support of the Secretary's interpretation.  However, the documentary evidence establishes that OSHA Deputy Director for Federal Compliance and State Programs Wilson, OSHA Assistant Regional Administrator Holder, and "Herbert Stokinger of the A.C.G.I.H. TLV Committee" all agreed with Bunge's interpretation.  Thus, industrial hygienists obviously disagree on the meaning of the provision.

The record also contains no support for the assertion that the grain-handling industry understands that grain dusts are included within the terms ''inert, or nuisance dust."  Judging from the testimony of the witnesses, the term "nuisance dust" appears to be meaningless to anyone who is not an industrial hygienist.  As for the term "inert dust," it has two very distinct meanings rather than a single, commonly understood meaning.  The record shows that industrial hygienists are alone in their understanding that this term refers to biological inertness.  The witnesses who were not industrial hygienists understood this term as referring to chemical inertness and, thus, because grain dusts are not chemically inert, the standard would apparently exclude rather than include them. Thus, the Secretary failed to prove that there is any "common understanding" in the grain-handling industry of the terms "inert or nuisance dust."  At most, the Secretary established an awareness within the grain-handling industry of the publicity surrounding the Secretary's attempts to regulate grain dust under the inert or nuisance dust provision of the mineral dust standard.[[16]]  However, the Constitution requires fair notice of the requirements of the law, not fair notice of an agency's enforcement position.

Moreover, adoption of the Secretary's interpretation of the inert or nuisance dust provision would deprive the grain handlers of their due process right to fair notice of the standard's requirements.  The Secretary's position conflicts with the principle of regulatory construction that standards are not to be construed in a way that deprives employers of fair notice.  See Diamond Roofing Co. v. OSHRC, 528 F.2d 645 (5th Cir. 1976).  Cf. Marshall v. Anaconda Co., 596 F.2d 370 (9th Cir. 1979) (court rejects interpretation of § 1910.179 (b)(2) that raises "serious question(s) regarding its validity").  As our discussion above indicates, there is nothing in the mineral dust standard generally, or in the inert or nuisance dust provision in particular, that places employers on notice that the standard applies to grain dust.  On the contrary, the manner in which the Secretary adopted the mineral dust standard deprived employers of any notice they might otherwise have been given.

In the process of developing the mineral dust standard, the Secretary did not give even indirect notice of an intent to govern vegetable dusts.  When the ACGIH adopted its version of Table Z-3, it accompanied its listings with explanatory materials indicating that at least one set of TLV's, for "'Inert' or Nuisance Particulates," applied to both mineral and vegetable dusts.  See note 11 supra. But when the Secretary incorporated these TLV's into 41 C.F.R. § 50-204.50, see note 10 supra, he did not incorporate the ACGIH's list of examples and its definitional sections.  Moreover, when the Secretary later adopted the Walsh-Healey standard as an established Federal standard under section 6(a) of the Act and repromulgated it as an OSHA standard, he eliminated any reference to the ACGIH and its TLV's as the indirect source of the OSHA standard.  As a result, there is absolutely nothing in the OSHA standard to indicate that any of its provisions apply to organic dusts.  The mineral dust standard contains no definition of the terms "inert or nuisance dust," no list of examples, and no other clarifying information.[[17]]

The Secretary nevertheless maintains that we should construe the mineral dust standard to effectuate the intent of the ACGIH. Deference to the intent of the ACGIH is not proper here, however, because there was nothing to give the public notice that the ACGIH's intent was carried over when the Secretary adopted the standard.  It is axiomatic that OSHA standards must be interpreted in accordance with the natural and plain meaning of their words; they cannot be construed to mean what the agency may have intended but did not adequately express.  Diamond Roofing Co. v. OSHRC, 528 F.2d at 649.  See also Bechtel Power Corp., 85 OSAHRC , 12 BNA OSHC 1509, 1511, 1985 CCH OSHD ¶ 27,381 at p. 35,453 (No. 80-4764, 1985), appeal filed, No. 85-7661 (9th Cir. Nov. 27, 1985) (Commission cannot construe a standard "to mean what it does not say").  Adoption of a strained interpretation of the mineral dust standard, an interpretation that bears no reasonable relationship to the standard's plain words, would not serve the purposes of the Act because the standard would not be effective in guiding the conduct of employers.  See Bethlehem Steel Corp. v. OSHRC, 573 F.2d 157, 161-162 (3d Cir. 1978); Diamond Roofing Co. v. OSHRC, 528 F.2d at 650; Lisbon Contractors, Inc., 84 OSAHRC, 11 BNA OSHC 1971, 1973-74, 1984 CCH OSHD ¶ 26,924 at p. 34,500 (No. 80-97, 1984).  We therefore reject the Secretary's interpretation of the mineral dust standard and interpret that standard in accordance with its plain meaning.

II

A

As noted previously, in Docket No. 77-1622 the Secretary also alleged that Bunge's failure to reduce airborne levels of soybean dust on the fourth floor bin deck and the shipping gallery violated the crystalline quartz silica provision of the mineral dust standard.   The judge affirmed this alternative allegation without expressly discussing the scope of the crystalline quartz silica provision.  However, the judge implicitly adopted the interpretation that was set forth in the testimony of IH Gribble and Dr. Thomas A. Richard, the Secretary's two expert witnesses in the field of industrial hygiene.

According to these witnesses, OSHA does not have a PEL for pure crystalline quartz silica,[[18]] but rather, the PEL's established in Table Z-3 govern all silica-bearing dusts, that is, any dust that includes crystalline quartz silica as one of its components. Accordingly, these witnesses reasoned, the crystalline quartz silica provision applies to the soybean dust at Bunge's workplace because that dust contained quartz.

The witnesses also testified that the PEL's for inert or nuisance dust and for crystalline quartz silica are interrelated.  If the number 0 (representing dust with no quartz in it) is inserted into the crystalline quartz silica formulas, the result is the PEL's for inert or nuisance dust--15 mg/m3 for total dust and 5 mg/m3 for respirable dust.  The formulas operate in such a manner as to create a sliding scale of PEL's depending on the percentage of the total dust or the total respirable fraction of the dust that is crystalline quartz silica.  In this way, the PEL's are lowered as the percentage of the silica in the dust becomes higher.  The upper limit of the sliding scale is the PEL for inert or nuisance dust (containing no quartz); the lower limit is the PEL for pure quartz dust.

IH Gribble further illustrated the operation of the crystalline quartz silica provision by describing how he arrived at his conclusion that the PEL's for crystalline quartz silica at Bunge's workplace on April 27 had been exceeded.  As explained in Part IA supra, approximately two months after Gribble obtained the three air contaminant samples during his inspection of Bunge's grain elevator, the samples were transmitted from OSHA's New Orleans Area Office to OSHA's testing laboratory in Salt Lake City.  There, lab chemist John C. Germ conducted an x-ray diffraction analysis on the samples.  Based on his analysis, Germ concluded that each sample contained crystalline quartz silica.  The x-ray diffraction analysis also resulted in a quantitative determination as to the amount of quartz in each of three samples.  Specifically, Germ determined the amount of crystalline quartz silica as a percentage of the total weight of the dust collected on the filter.  He recorded the following quantitative results:

Filter 030 (shipping gallery, total dust)         2.4% quartz
Filter 044 (bin deck, respirable dust)            3.5% quartz
Filter 051 (bin deck, total dust)                    4.6% quartz

At the hearing, Germ acknowledged that x-ray diffraction analysis should not be used to analyze total dust samples.  On the standardized forms on which he had recorded his analytical results, printed in such a manner that it cannot be overlooked, was the following notation:

OSHA X-ray Si02 Procedure.  This X-ray analysis is accurate only for respirable samples of (less than 10 micrograms) diameter. Nonrespirable samples should be analyzed colorimetrically by P & CAM 106.

Shown this standardized notation, Germ did not deny that x-ray diffraction analysis was considered by OSHA itself to be an inaccurate method of analyzing total dust samples.[[19]]  Instead, he testified to the effect that he had relied on the results of his analysis of the total dust samples only to corroborate the results of his analysis of the respirable dust sample (filter 044).

Nevertheless, IH Gribble used these results to compute the PEL's for both respirable crystalline quartz silica and total crystalline quartz silica at Bunge's workplace on April 27.  First, Gribble looked to the two formulas in Table Z-3 that are used to determine the PEL's for respirable crystalline quartz silica and for total crystalline quartz silica.  According to the witness, the notations "% Si02" and "% S202" (apparently a typographical error) refer to the percentage by weight of the total dust collected (i.e., either all dust in the employee's breathing zone or all respirable dust) that is crystalline quartz silica.  Here, these were the figures supplied by lab chemist Germ, i.e., 2.4%, 3.5%, and 4.6%.  Using these figures, Gribble calculated the controlling PEL'S.[[20]]  Gribble's next step was to compare each employee's 8-hour time weighted average (TWA) exposure with that employee's corresponding PEL. According to Gribble, the relevant exposure for purposes of this comparison was the previously-determined 8-hour TWA exposure for either all dust or all respirable dust in the employee's breathing zone, which in this case measured the amounts of soybean dust (total or respirable) to which the three employees at issue were exposed on April 27.  Upon making these comparisons, Gribble concluded that in each instance the applicable PEL had been exceeded.[[21]]

In his decision, Judge Oringer credited the Secretary's evidence on the meaning of the crystalline quartz silica provision and the percentage of quartz in the Bunge samples.  He found that all three of the Bunge employees whose exposures were sampled had been exposed to levels of quartz-bearing dust in excess of the mineral dust standard's PEL's for total and respirable crystalline quartz silica.  He also found that Bunge had failed to implement feasible engineering controls to reduce the dust levels within permissible limits.  Accordingly, he sustained the Secretary's alternative charge under the crystalline quartz silica provision of the mineral dust standard.

On review, Bunge argues that the judge erred in affirming the alleged violation of the crystalline quartz silica provision.  Bunge suggests that the judge's interpretation and application of this provision may have been erroneous.  In any event, it contends that the provision cannot be interpreted and applied as the Secretary and the judge have done without depriving grain handlers of their due process rights to fair notice of the standard's requirements.

Bunge raises two fair notice issues in support of its claim that "this virtually indecipherable regulation does not pass constitutional muster."   First, it argues that the provision is unenforceably vague because the employer cannot tell whether it is in compliance with the regulation.  Bunge notes Gribble's testimony concerning his calculations of over-exposure and asserts that there is nothing in the mineral dust standard or its crystalline quartz silica provision that gives notice that the PEL, once calculated, should be compared with the 8-hour TWA exposure for all of the dust collected in the sample, including both the organic and inorganic components of the dust.

The second fair notice issue is related to st it is error to treat it as nuisance dust when considering a [crystalline quartz] silica violation."

B

We have already concluded that the mineral dust standard applies only to mineral dusts.  Because it is undisputed that soybean dust is not a mineral dust, the crystalline quartz silica provision of the mineral dust standard cannot be applied to the cited conditions. Accordingly, this alternative allegation in Docket No. 77-1622 must also be vacated.

In reaching this conclusion, we are guided by the principle that two related provisions of single standard must be interpreted in the context of the standard as a whole.  See State Highway Commission of Missouri v. Volpe; 2A Sutherland Statutory Construction § 46.05.  It would be inconsistent for us to hold that the inert or nuisance dust provision does not apply to soybean dust, while the crystalline quartz silica provision of the same table does apply to soybean dust.   Bunge cites to the testimony of the Secretary's witnesses that the PEL's for inert or nuisance dust and for crystalline quartz silica, as they are interpreted by the Secretary, are in effect PEL's for nuisance dust containing quartz.  Therefore, since the PEL's for inert or nuisance dust do not apply to soybean dust, the formulas for reducing those PEL's when quartz is present in the dust also do not apply.

We find considerable merit in Bunge's analysis.  However, we also observe another fundamental inconsistency in attempting to apply the crystalline quartz silica provision to grain dust.  We vacate the nuisance dust allegation on ground that the inert or nuisance dust PEL's are set forth in a table that applies only to mineral dusts.  The crystalline quartz silica PEL's are included in the same table, Table Z-3.  The mineral dust standard does not give fair notice that its inert or nuisance dust provision applies to a dust that is predominantly organic.  We find the same notice problem in applying a different provision of the same standard to the same dust. Since Table Z-3 is limited in its coverage to mineral dusts, we conclude that none of the provisions of the mineral dust standard can be applied to soybean dust.

We also agree with Bunge's argument that the Secretary's interpretation of the crystalline quartz silica provision deprives grain handlers of their due process rights to fair notice of the standard's requirements.  We note that, in contrast to the inert or nuisance dust allegation, there is not even a claim by the Secretary of a common understanding that the crystalline quartz silica PEL's are applicable to grain dust.  Certainly, the Secretary cannot rely on any publicity surrounding his enforcement position, for this appears to be the first and only effort to apply this provision to this type of dust.[[22]]  In fact, we are unaware of any other enforcement action where the Secretary sought to apply the crystalline quartz silica provision to a dust that was not wholly, or at least predominantly, silica dust.  Nor is there any legislative history to support the Secretary's interpretation of this provision.  The 1968 ACGIH-TLV's pamphlet, which is the source document, provides no more guidance on the meaning and application of the crystalline quartz silica provision than does the OSHA mineral dust standard itself.  Neither the standard, the source document, nor any other written materials that we are aware of explains the Secretary's interpretation and application of the provision.  Indeed, our only information on these matters is the testimony of IH Gribble and Dr. Richard.

We are left then with the language of the standard, which Bunge correctly characterizes as "virtually indecipherable."  The standard states that "exposure to any material listed in Table Z-3" shall not exceed the PEL's "given for that material in the table."  The "material" that is listed is crystalline quartz silica and the table in which it is listed is captioned "Mineral Dusts."  To begin with, we could not reasonably expect that an employer looking through the Secretary's standards to find the PEL's for grain dust would read the table and conclude that it had found the applicable PEL's.

Even if the employer made it over this initial hurdle, it would have considerable difficulty in determining whether it had exceeded the PEL's.  It would have to guess the meaning of the notations "% Si02" and "% S202 in the two formulas for determining the PEL's.  Is one of them a typographical error or do they refer to two different substances?  Do they refer to all silica in the sample or just the silica that is crystalline quartz?  The employer would then have to decide whether to state the percentages as whole numbers (as the witnesses did) or as their decimal equivalents (as is more common in performing mathematical computations).   Finally, once the employer calculated the PEL's, it would have to recognize that, contrary to the language of the standard, those PEL's do not govern the amounts of total quartz or respirable quartz in the air but rather the amounts of total dust or respirable dust, including both the organic and inorganic components of the dust.  In view of these many uncertainties and ambiguities, we conclude that a reasonable employer in the grain-handling industry would not understand from reading the crystalline quartz silica provision of the mineral dust standard that it is to be interpreted and applied in the manner described by the Secretary's witnesses.  The provision as applied to the facts of this case does not give fair notice of its requirements.[[23]]

III

The separate citations in Docket Nos. 78-0838 and 78-2213 allege violations of 29 C.F.R. §§ 1910.1000(c) and (e), based on the provision of section 1910.1000 that has been referred to throughout this decision as "the inert or nuisance dust provision" of the "mineral dust standard."  Neither case involves any allegation under the crystalline quartz silica provision of the mineral dust standard.[[24]]  No hearing has been held in either case.  Instead, the Secretary and Bunge entered into stipulated settlement agreements.  The two agreements are essentially identical.   The key provision of both agreements, as it is stated in the agreement filed in Docket No. 78-0838, provides:

Whereas each of the parties herein have spent a substantial amount in the preparation and trial of OSHRC Docket No. 77-1622 . . . ; and whereas the identical issue is presented herein; the parties therefore stipulate and agree to be bound by the highest decision rendered in OSHRC Docket No. 77-1622, whether by the Occupational Safety and Health Review Commission, the United States Court of Appeals, or the United States Supreme Court, so that if grain dust ultimately is held to be a nuisance dust . . . within the meaning of . . . Table Z-3......, this matter shall be heard on the merits, and if grain dust ultimately is not held to be a nuisance dust . . . . this matter shall be dismissed.

After issuing his decision in Docket No. 77-1622, Judge Oringer issued separate decisions in Docket Nos. 78-0838 and 78-2213.  In both of these cases, he concluded that the issues were ripe for decision.  Accordingly, he applied his holding in Docket No. 77-1622 and vacated the citation items in the two later cases on the ground that the inert or nuisance dust provision does not apply to employee exposure to grain dust.  On review, the Secretary argues, and Bunge agrees, that the judge acted prematurely in vacating in citation items at issue in Docket Nos. 78-0838 and 78-2213.  The parties contend that the judge erred in failing to wait for "the highest decision rendered in OSHRC Docket No. 77-1622" within the meaning of their settlement agreements.

We disagree.  Judge Oringer acted properly in taking action to remove these two cases from this docket.  In addition, the parties have not been prejudiced as a result of the judge's action.  By deciding these three cases as a consolidated unit, we have accomplished the result the parties sought to achieve through their settlement agreement.  The inert or nuisance dust provision has been uniformly applied in all three cases, and all three cases remain open if our decision is appealed.

Accordingly, we review the merits of the judge's rulings on the contested citation items in Docket Nos. 78-0838 and 78-2213.  For the reasons stated previously, we agree with the judge that the citation items must be vacated because inert or nuisance dust provision of the mineral dust standard does not apply to employee exposure to grain dust.

IV

In Docket No. 77-1622, the judge's decision is affirmed with respect to the allegations under the inert or nuisance dust provision and reversed with respect to the allegations under the crystalline quartz silica provision.  In Docket Nos. 78-0838 and 78-2213, the judge's decisions are affirmed.  All citation items at issue on review in this consolidated proceeding, including alternative allegations, are vacated.

FOR THE COMMISSION

Ray H. Darling, Jr.
Executive Secretary

Dated:  April 22, 1986

The Administrative Law Judge decision in this matter is unavailable in this format.  To obtain a copy of this document, please request one from our Public Information Office by e-mail ( lwhitsett@oshrc.gov ), telephone (202-606-5398), fax (202-606-5050), TTY (202-606-5386).

FOOTNOTES:

[[1]] The term "mineral dust standard" will be used throughout this decision to refer to various related provisions of 29 C.F.R. §1910.1000 that, taken together, require employers to implement protective measures whenever their employees are exposed to mineral dust levels that exceed any of the permissible exposure limits ("PEL's") listed in Table Z-3 of §1910.1000.  "Inert or nuisance dust" is one of the listed substances that is regulated under the mineral dust standard.  The pertinent provisions of §1910.1000 are the following:

§1910.1000 Air contaminants.

An employee's exposure to any material listed in Table Z-1, Z-2, or Z-3 of this section shall be limited in accordance with the requirements of the following paragraphs of this section.

(c) Table Z-3:  An employee's exposure to any material listed in Table Z-3, in any 8-hour work shift of a 40-hour work week, shall not exceed the 8-hour time weighted average limit given for that material in the table.

TABLE Z-3 -- MINERAL DUSTS

(e) To achieve compliance with paragraph (a) through (d) of this section, administrative or engineering controls must first be determined and implemented whenever feasible.   When such controls are not feasible to achieve full compliance, protective equipment or any other protective measures shall be used to keep the exposure of employees to air contaminants within the limits prescribed in this section. . . . Whenever respirators are used, their use shall comply with § 1910.134.

[[2]] "Crystalline quartz silica" is another substance that is regulated under the "mineral dust standard."  In addition to containing the PEL's for "inert or nuisance dust," Table Z-3 of § 1910.1000 also sets forth the following PEL's for "crystalline quartz silica":
TABLE Z-3 -- MINERAL DUSTS

[[3]] Bunge presents three challenges to the propriety of the Secretary's enforcement procedures in Docket No. 77-1622.  First, it argues that, contrary to the requirements of § 8(a)(2) of the Act, 29 U.S.C. § 657(a)(2), the underlying inspection was not conducted "within reasonable limits and in a reasonable manner."   More specifically, it contends that the inspection was unreasonable because the air contaminant samples taken by the Secretary were obtained under conditions that were not representative of the conditions that usually existed at its workplace.  Bunge also argues that the judge erred in granting two motions by the Secretary to amend the allegations of violation contained in the citation.  Finally, Bunge charges that, during the period between the filing of its notice of contest and the beginning of the hearing, the Secretary engaged in a series of misrepresentations and abuses of procedure that in combination "subverted the Act's fundamental process."  According to Bunge, the Secretary thereby deprived it of the administrative and procedural due process guaranteed to it by law.

[[4]] Total dust samples collect all dust in the breathing zone, i.e., they are "nonspecific."  Respirable dust samples are also "nonspecific" in the sense of capturing any kind of particulate material in the air.  However, they are designed to collect only respirable particles, which are 10 microns or less in length.  This size separation occurs when a device called a "cyclone" is used in conjunction with the sampling device.

[[5]] The samples were taken in the breathing zones of three Bunge employees.   A sampling device containing a filter was placed on Lionel McZeal while he worked on the shipping gallery.  The filter collected 5.81 mg of total dust.  Using this figure in conjunction with other relevant data, IH Gribble calculated McZeal's 8-hour time weighted average (TWA) exposure to be 8.06 mg/M3. McZeal's exposure was therefore within the limits established for total inert or nuisance dust, that is, it was less than the 15 mg/M3 PEL set forth in Table Z-3.  A second sampling device with a cyclone attached so that only respirable dust would be collected was placed on Rickie Cure as he worked on the fourth floor bin deck.  The filter collected 9.96 mg of respirable dust.  Cure's 8-hour TWA exposure was calculated to be 12.14 mg/M3.  Thus, Cure's exposure exceeded the 5 mg/M3 PEL for respirable inert or nuisance dust.  The third sampling device was placed on Joseph Charles while he worked on the fourth floor bin deck.  The filter collected 18.94 mg of dust (total dust).  The 8-hour TWA exposure for Charles was calculated to be 26.05 mg/M3.  This exposure exceeded the 15 mg/M3 PEL for total inert or nuisance dust.

[[6]] The Secretary charged a violation of the mineral dust standard on the shipping gallery based solely on the sampling of McZeal's exposure, which did not establish a violation of the inert of nuisance dust provision of the cited standard.   See note 5 supra.  There is no explanation in the record for this anomaly.

[[7]] The third and final lab analysis was conducted several months later, apparently for the purpose of reconciling the conflict between the first two analyses.   On November 15, lab chemist Dixon conducted a second petrographic analysis on one of the samples.  This analysis confirmed Germ's report that crystalline quartz silica was present in the sample.  Dixon was unable to make a quantitative determination.   At the hearing, Dixon testified that various treatments of the sample between June 27 and November 15 had removed almost all of the material on the filter "and just about everything I saw at that point was quartz."  Dixon hypothesized that the crystalline quartz silica he saw on November 15 had been in the sample all along, but that he had been unable to see it on June 27 because of the "interference" of an organic "coating."  In his opinion, when this coating was removed, primarily through "chemical ashing" (treatment with phosphoric acid), he was able to see the quartz and confirm its presence in the sample.

[[8]] The "A.C.G.I.H." is the American Conference of Governmental Industrial Hygienists.  As discussed more fully infra, its "TLV Committee" drafted the standard that was the indirect source of the mineral dust standard.  It appears from the source document that "Herbert E. Stokinger, Ph.D.," was the chairman of the committee that drafted the standard.  See Exh. J-1 (for judicial notice) at page 26.  In addition, a second ACGIH publication introduced into the record as Exh. J-2 (for judicial notice) lists "Herbert E. Stokinger, Ph.D." as a member of the "1977 TLV Airborne Contaminants Committee."  The record does not otherwise identify Stokinger or elaborate on the telephone conversation with him.

[[9]] On February 2, 1978, approximately three weeks before the hearing in Docket No. 77-1622, OSHA issued Program Directive #300-11, which expressly cancelled the July 13 Wilson-Tice memo.  In this document, which was signed by the same Deputy Director Wilson, OSHA interpreted the Table Z-3 PEL's for inert or nuisance dust as applying to all types of nuisance dust, both organic and mineral, and as specifically including soybean dust.

[[10]] 29 C.F.R. § 1910.1499 identifies the source of § 1910.1000 (including the mineral dust standard) as 41 C.F.R. § 50-204.50. This was a standard originally issued under the Walsh-Healey Act and later adopted as an "established Federal standard" under § 6(a), 29 U.S.C. § 655(a), of the Occupational Safety and Health Act.  In turn, the Walsh-Healey standard was largely based on a non-governmental consensus standard developed by the ACGIH (American Conference of Governmental Industrial Hygienists).  In particular, the mineral dust PEL's established under 41 C.F.R. § 50-204.50 (and later published in Table Z-3 of § 1910.1000) were derived from an ACGIH pamphlet titled Threshold Limit Values of Air-borne Contaminants (sic) for 1968:  Recommended and Intended Values (hereafter "1968 ACGIH-TLV's").

We note that the terms "threshold limit value (TLV)" and "permissible exposure limit (PEL)" are often used interchangeably. However, there is a difference in their meaning.  As stated in the preface to the 1968 ACGIH-TLV's pamphlet, a TLV is an airborne concentration of a substance that represents the level at "which it is believed that nearly all workers may be repeatedly exposed, day after day, without adverse effect."  The nature of this adverse effect "may differ from substance to substance; protection against impairment of health may be the guiding factor for some, whereas reasonable freedom from irritation, narcosis, nuisance or other forms of stress may dominate the basis for others."   The TLV is "based on the available information from industrial experience, from experimental human and animal studies, and when possible, from a combination of the three."

Thus, "TLV" is an industrial hygienist's term and, as the ACGIH explained, the limits "are intended for use in the field of industrial hygiene."   In contrast, "PEL" is a legal term referring to a limit that may not be exceeded or a limit that triggers certain legal obligations when it is exceeded.   When the Secretary of Labor incorporated the TLV's developed by the ACGIH into his occupational health standards, he thereby transformed the TLV's into legally enforceable PEL's.

[[11]] The 1968 ACGIH-TLV's pamphlet refers to "'Inert' or Nuisance Particulates" and sets forth a list of "Some 'Inert' or Nuisance Particulates" in its appendix.  The list includes both organic and inorganic substances and both mineral and vegetable dusts.  For example, four of the components of grain dust are included on the list--calcium carbonate, cellulose, starch and sucrose. However, neither grain dust generically nor any particular type of grain dust is included on the list.  The pamphlet also contains a section in the preface that explains the terms "'Inert' or Nuisance Particulates."  This section similarly refers to both organic and inorganic substances as examples.  The Secretary also introduced into the record the 1977 version of the ACGIH pamphlet, which was the most recent version at the time of hearing.  That pamphlet similarly includes a list of particulates and an explanatory section that indicate an intent to include organic dusts within the coverage of the TLV's.

[[12]] The same rules of interpretation are applicable in interpreting both statutes and administrative regulations, such as the Secretary's occupational safety and health standards.  See, e.g., Ohio-Sealy Mattress Mfg. Co., 83 OSAHRC 27/C14, 11 BNA OSHC 1377, 1380-1381, 1983-84 CCH OSHD ¶ 26,528, p. 33,805 (No. 79-5600, 1983).

[[13]] Lab chemist Dixon, who was accepted by the judge as an expert witness in mineralogy, outlined the principal subcategories of silica.  The two basic types are crystalline silica, which is commonly called "free silica," and amorphous silica, which is not crystalline and therefore not classified scientifically as a mineral.   Amorphous silica includes two subcategories--diatomaceous earth and dehydrated silica gel.  Free silica exists as quartz (i.e., crystalline quartz silica), tridymite, cristobalite, coesite and stishovite.  1 PATTY'S INDUS. HYGIENE & TOXICOLOGY 185 (G.D. Clayton & F.E. Clayton 3d rev. ed. 1978)  Each of these last-mentioned substances is a "polymorph" of free silica, that is, each is a mineral that has the chemical formula "Si02".  Quartz is the most common of these substances, not only in nature but also in occupational environments.

[[14]] Lab chemist Dixon stated that three of the substances listed in Table Z-3 are not classified scientifically as "minerals": amorphous silica because it is not crystalline, Portland cement (a silicate) because it does not occur in nature, and coal dust because coal is organic.  We assume that this testimony accurately describes how a mineralogist would classify the substances.  Nevertheless, it is clear on this record that all of the substances in Table Z-3 are considered to be "mineral dusts" under the common usage of the term "mineral."   Even the Secretary's witnesses admitted this fact.  For example, IH Gribble testified that all of the Table Z-3 substances are mineral dusts with the exception of coal dust.  Even coal, he conceded, is "termed by many to be a mineral because it's mined from the ground."  Dr. Richard gave similar testimony.  With respect to coal dust, he stated that coal is considered to be a "natural mineral deposit" despite its organic composition.

[[15]] At the hearing, Dr. Thomas J. Culpepper, a witness for Bunge who was found to be an expert in environmental analytical chemistry, testified that the term "inert" to a chemist means nonreactive.  For this reason, he concluded that organic dusts such as grain dusts would not be classified as inert or nuisance dusts.

[[16]] The Secretary introduced various exhibits, as well as the testimony of industrial hygienist Gribble and Dr. Richard, showing that, prior to the instant citation against Bunge, both federal and state officials had issued citations to several grain handlers for dust levels exceeding the inert or nuisance dust PEL's.  The Secretary also proved that his enforcement actions had been publicized both in trade journals and in a magazine published by OSHA.  In his brief to the Commission, the Secretary cites this evidence as proving that the term "nuisance dust" is commonly understood within the grain-handling industry as including grain dust.  He cites no other evidence in support of that proposition.

[[17]] We further observe that, even if an employer were aware of the standard's ACGIH precursors, it would be very difficult for him to discover the intent of the ACGIH in developing its TLV's for inert or nuisance dust.  At the hearing, IH Gribble testified that it had been difficult for him--a professional industrial hygienist and a member of the ACGIH--to obtain a copy of the 1968 pamphlet so that he could review the ACGIH's explanatory sections.  Certainly today it would be even more difficult for an employer engaged in grain handling to obtain a copy.  Under these circumstances, it would be unreasonable to expect employers to refer to source materials, and especially these ACGIH source materials, outside of the OSHA standard itself in order to give to the standard's terms a meaning that is contrary to their commonly understood meaning.

[[18]] According to the witnesses, PEL's for pure crystalline quartz silica can be determined by inserting the number 100 (representing 100% quartz) into the two formulas set forth in the mineral dust standard.  See note 2 supra.

[[19]] Even if we were to conclude that the mineral dust standard applied to grain dust containing silica, we could not sustain the citation with respect to the allegation that total dust levels exceeded the PEL's for crystalline quartz silica, since those allegations rest solely on Germs X-ray diffraction analysis of filters 030 and 051.

[[20]] Gribble further testified that the formulas refer to whole number percentages rather than their decimal equivalents, e.g., 2.4 rather than .024.  Thus, Gribble inserted the number 3.5 into the respirable dust formula to obtain a respirable dust PEL of 1.81 mg/M3 for the fourth floor bin deck.  He inserted the numbers 2.4 and 4.6 into the total dust formula to obtain total dust PEL's of 6.82 mg/M3 and 4.54 mg/M3 for the shipping gallery and the fourth floor bin deck, respectively.

[[21]] At the hearing, Gribble in effect conceded that no charge should have been made with respect to crystalline quartz silica on the shipping gallery.  Gribble referred to guidelines set forth in an OSHA Industrial Hygiene Manual, although he did not state which edition of the manual or which section he was referring to.  Under those guidelines, as described by the witness, once he had determined the applicable PEL, he should then have adjusted it by multiplying the PEL by the "statistical correction factor."  This adjustment is made to take into account the possibility of error in the collection of the sample and in the laboratory determination of the percentage of crystalline quartz silica.  It accomplishes this goal by increasing the PEL to add in a margin of error.  Gribble also testified that, for a total dust sample, the statistical correction factor was 1.25.  Thus, the adjusted PEL for total crystalline quartz silica on the shipping gallery was 8.5 mg/M3 (1.25 x 6.82).  Since Lionel McZeal's 8-hour TWA exposure was only 8.06 mg/M3, exposure to excessive dust levels was not established under the Secretary's internal guidelines.

[[22]] At the hearing, the Secretary's counsel stated that, to the best of his knowledge, this was the first time a granary had ever been charged with a violation of this provision.  In addition, the two lab chemists who analyzed the Bunge samples indicated that they were probably the first grain dust samples the Salt Lake City testing laboratory had ever analyzed for silica content.  While these chemists further testified that similar analyses were conducted after the analysis of the Bunge samples, we are unaware of any subsequent citation of a grain handler under the crystalline quartz silica provision.

[[23]] Indeed, we are not persuaded that the Secretary's interpretation and application of the crystalline quartz silica provision is consistent with the intent of the ACGIH, which drafted the source TLV's.  Although IH Gribble and Dr. Richard gave consistent testimony to the effect that the PEL's cover all silica-bearing dusts, neither cited any document stating that the PEL's should be applied to predominantly organic dusts such as grain dust.  There is certainly nothing in the ACGIH source document that supports this conclusion.

More importantly, however, we are unable to conclude that application of the crystalline quartz silica provision to grain dust would have the effect intended by the ACGIH.  Based on the ACGIH's explanation of how it develops its TLV's, it appears likely that the TLV's for crystalline quartz silica were primarily designed to protect employees from fibrotic changes to the lung, including specifically the risk of contracting silicosis.  Yet, the documentary evidence presented by the Secretary suggests that it is virtually impossible to contract silicosis through exposure to grain dust.

In particular, we note the epidemiological survey and research study admitted into evidence as Secretary's Exhibit B.  Williams, Skoulas & Merriman, Exposure to Grain Dust:  I.  A Survey of the Effects, 6 J. OCCUP. MED. 319 (Aug. 1964) (hereafter Williams).  Significantly, these researchers observed that, with the exception of a single case reported in 1944, "there has been no report in the literature supporting the possibility that free silica in grain dust might be a factor in the resultant respiratory disease." Williams at p. 320.  Indeed, these researchers unequivocally expressed their opinion that free silica is not a factor:

The dust analyses indicate that most of the free silica is in the soil fraction of the dust.  It is known that lifetime exposure to the dust of desert sands does not lead to the development of silicosis.  Likewise, there is no evidence that the free silica in soil dust can produce the disease.  It is unlikely that the very small amount of free silica in the organic fraction could produce silicosis.   Moreover, the silica is closely bound physically to the organic material and there is none of the crushing or grinding of silicious material which creates a silicosis hazard.  Therefore . . . there is strong evidence against silica playing any role in the respiratory disease associated with exposure to grain dust.  Williams at p. 326.   In the absence of any reason to believe that the quartz within grain dust creates any hazard whatsoever, we cannot conclude that the Secretary's interpretation of the crystalline quartz silica provision serves the purpose intended by the ACGIH.

[[24]] Also at issue in Docket No. 78-2213 are alleged violations of two subsections of 29 C.F.R.§ 1910.134.  Because these requirements are incorporated by reference into the mineral dust standard--specifically, the last sentence of §1910.1000(e)--the parties agree that they can be applied to the cited working conditions only if the inert or nuisance dust provision can be applied to those conditions.