“SECRETARY OF LABOR,Complainant,v.BUNGE CORPORATION,Respondent.OIL, CHEMICAL AND ATOMIC WORKERSINTERNATIONAL UNION AND ITS LOCAL 4-447,Authorized EmployeeRepresentative(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 andHealth Review Commission under 29 U.S.C. ? 661(i), section 12(j) of theOccupational Safety and Health Act of 1970, 29 U.S.C. ?? 651-678 (\”theAct\”). The Commission is an adjudicatory agency, independent of theDepartment of Labor and the Occupational Safety and HealthAdministration (\”OSHA\”). It was established to resolve disputes arisingout of enforcement actions brought by the Secretary of Labor under theAct and has no regulatory functions. See section 10(c) of the Act, 29U.S.C. ? 659(c).The three cases have been consolidated on review under Commission Rule9, 29 C.F.R. ? 2200.9. because they involve common parties and commonquestions of law and fact. Bunge Corporation (\”Bunge\”) is one of thelargest employers within the international grain-handling industry. Asa result of separate inspections of its facilities in Destrehan,Louisiana (Docket No. 77-1622), Galveston, Texas (No. 78-0838), andOsceola, Arkansas (No. 78-2213), Bunge was issued citations allegingviolations of the inert or nuisance dust provision of the mineral duststandard at all three of these workplaces.[[1]] The principal issue onreview is whether Administrative Law Judge David G. Oringer erred invacating these citations on the ground that the inert or nuisance dustprovision does not apply to grain dust. Also on review, in Docket No.77-1622, are the judge’s finding of a violation of the crystallinequartz silica provision of the mineral dust standards[[2]] and thejudge’s rejection of various procedural defenses.[[3]]We conclude that neither the inert or nuisance dust provision nor thecrystalline quartz silica provision of the mineral dust standard can beapplied to regulate employee exposure to grain dust. On this ground, wevacate each of the citation items on review. In light of ourdisposition, we need not reach the procedural issues raised by Bunge inDocket No. 77-1622.IAOn March 4, 1977, OSHA began an inspection of Bunge’s marine terminalgrain elevator at its export port facility in Destrehan, Louisiana. Thecitation at issue in Docket No. 77-1622 is based on three aircontaminant samples taken by industrial hygienist (\”IH\”) William D.Gribble during that inspection. Two total dust samples and onerespirable dust sample were obtained on April 27.[[4]] The recordestablishes, and the parties agree, that the dust collected in thesesamples was soybean dust, which is a type of grain dust.[[5]]As a result of its inspection, OSHA issued a citation to Bunge allegingviolations 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 onthe shipping gallery were exposed on April 27 to levels of dust thatexceeded the mineral dust standard’s permissible exposure limits forrespirable inert or nuisance dust and for total inert or nuisancedust.[[6]] The citation further alleged that Bunge failed to determineand implement feasible administrative or engineering controls to reducethose dust levels within permissible limits.Bunge contested the citation and, in its notice of contest, requested aninformal conference with OSHA. At this conference, Bunge argued thatthe inert or nuisance dust provision does not apply to the citedconditions because Table Z-3 applies only to mineral dusts, and graindust is not a mineral dust. OSHA’s representatives indicated that theywould take Bunge’s contentions under advisement.Two days later, the Secretary obtained an extension of time to file thecomplaint in Docket No. 77-1622. This additional time was used for twopurposes–to obtain a laboratory analysis of the three dust samplescollected on April 27 and to consult with OSHA’s national office on thelegal and policy questions raised by Bunge about the scope of the standard.On June 20, the Bunge air contaminant samples were transmitted fromOSHA’s New Orleans Area Office to OSHA’s testing laboratory in Salt LakeCity. The lab was asked to determine if there was any mineral contentin the samples. Three separate analyses were conducted for thispurpose. On June 27, lab chemist Willard C. Dixon conducted apetrographic analysis, which is essentially no more than a visualexamination through a microscope using polarized light. Dixon saw onlyorganic materials in the three samples. He saw no particles ofcrystalline quartz silica or any other mineral. He reported to hissupervisor that his analysis \”yielded 100% soybean dust.\”On July 8, lab chemist John C. Germ conducted an x-ray diffractionanalysis on the samples. The purpose of this far more sophisticatedanalysis was to determine whether two specific substances–crystallinequartz silica and cristobalite–were present in the samples. Based onhis analysis, Germ concluded that the samples did not containcristobalite, but did contain crystalline quartz silica. The quartzcontent of each sample was calculated to be less than 5% by weight ofall the dust collected. On July 11, Germ reported his results to theNew Orleans Area Office. Using these results, IH Gribble computed thePEL’s for crystalline quartz silica at Bunge’s workplace and concludedthat these PEL’s had been exceeded.[[7]]During the same time period that the Secretary’s representatives wereawaiting the results of the laboratory analysis, they also sought toresolve Bunge’s contention that the inert or nuisance dust provision ofthe mineral dust standard does not apply to soybean dust. Initially,this question was presented to OSHA’s Regional Office in Dallas, whichin turn sought a determination at the national level. Thus, on June 30,a memorandum (\”the Holder memo\”) was sent from an official in the DallasRegional Office (Holder) to the Office of Field Coordination, a branchof the national OSHA office. The national office was informed that thequestion of whether the inert or nuisance dust provision applies tosoybean dust had been raised as an issue in a contested case. It wasalso informed of a \”telephone discussion with Herbert Stokinger of theA.C.G.I.H. TLV Committee who agrees that only those substancescontaining 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 Complianceand State Programs (Wilson) to the Dallas Regional Administrator (Tice).The OSHA Deputy Director concluded that vegetable and animal dusts arenot covered under Table Z-3 because they are not \”mineral dusts.\” Inparticular, the memorandum stated, \”[s]oybean dust is a vegetable dustand 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 bothlab chemist Germ’s report on the quartz content of the three samples andthe Wilson-Tice memo on the inapplicability of the cited provision, theSecretary’s counsel filed the delayed complaint in Docket No. 77-1622. The complaint continued to allege noncompliance with the mineral duststandard based on Bunge’s failure to implement feasible administrativeor engineering controls to reduce excessive dust levels withinpermissible limits. The complaint also continued to base the charge ofexcessive dust levels on the three air contaminant samples that weretaken on the fourth floor bin deck and the shipping gallery on April27. However, the Secretary sought to amend the citation through thecomplaint to allege that the permissible exposure limits that wereexceeded on that date were the PEL’s for crystalline quarts silicarather than the PEL’s for inert or nuisance dust. Several weeks later,the Secretary moved to amend his pleadings so as to allege in thealternative noncompliance with the inert or nuisance dust provision,with the crystalline quartz silica provision, or with both provisions ofthe mineral dust standard. These motions to amend were granted despiteBunge’s objections. Accordingly, Docket No. 77-1622 proceeded to ahearing on the merits of the two alternative charges.BIn his decision in Docket No. 77-1622, Judge Oringer vacated theallegation that Bunge violated the inert or nuisance dust provision ofthe mineral dust standard, but affirmed the alternative allegation thatBunge violated that same standard’s crystalline quartz silicaprovision. He characterized the violation as nonserious, modified theabatement requirement, and assessed a penalty of $100.The judge concluded that the inert or nuisance dust provision cannot beapplied to regulate employee exposure to grain dust. In effect, heentered alternate holdings: (a) the provision does not apply to graindust because it applies only to mineral dusts or (b) even if grain dustfalls within the intended scope of the provision, it cannot be enforcedagainst grain handlers because it does not provide the constitutionallyrequired fair notice that it is applicable. Concerning the scope of thecited 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 despitethe fact that coal may have an organic base. In this cause the onlydusts collected were not mineral dust, but soybean dust, an organicnon-inert substance.On review, the Secretary argues that the judge erred in vacating theinert or nuisance dust allegation. He argues that the inert or nuisancedust provision should be applied to the cited facts based on the \”plainmeaning\” of the term \”nuisance dust,\” the intent of the drafters asrevealed in the history of the provision’s development, and the historyof the provision’s subsequent enforcement as a limitation on bothorganic and mineral dusts. In elaborating on his \”plain meaning\”argument, the Secretary contends that the term \”nuisance dust\” hasgenerally and consistently been understood, both in the industrialhygiene profession and in the grain-handling industry, to includevegetable as well as mineral dusts.The Secretary further claims that his enforcement action is consistentwith the intent of the ACGIH, the drafters of the inert or nuisance dustTLV’s.[[10]] He asserts that grain dust is biologically inert in thatit normally does not result in irreversible health effects such asscarring of the lungs. He points to provisions of two ACGIH-TLV’spamphlets that suggest that such biologically inert dusts are properlyclassified as \”inert or nuisance dust,\” regardless of whether they arevegetable or mineral dusts.[[11]] Accordingly, the Secretary reasons,grain dusts are covered by the OSHA mineral dust standard because theyare covered under the source standard.CWe conclude that the mineral dust standard applies only to mineraldusts. Because it is undisputed that soybean dust is not a mineraldust, neither of the provisions allegedly violated by Bunge applies tothe cited conditions. Accordingly, both of the alternative allegationsin 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, ofcourse, no more persuasive evidence of the purpose of a statute than thewords by which the legislature undertook to give expression to itswishes.\” _Griffin v. Oceanic Contractors, Inc_., 458 U.S. 564, 571(1982), quoting United States v. American _Trucking Associations_, 310U.S. 534, 543 (1940).[[12]] The standard requires employers to limitthe exposure of their employees within permissible exposure limitswhenever the employees are exposed \”to any material listed in TableZ-3.\” Table Z-3 is captioned \”Mineral Dusts\” and includes, in additionto the PEL’s for \”inert or nuisance dust\” and \”crystalline quartzsilica,\” PEL’s for two other \”polymorphs\” of silica (cristobalite andtridymite), 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, andthat all of the dusts listed in Table Z-3 are mineral dusts. Althoughthe Secretary attempted to prove that Table Z-3 includes three duststhat are not mineral dusts, the judge found against the Secretary onthis factual issue, and we conclude that his finding is supported by therecord.[[14]] We therefore adopt the judge’s finding that all of thematerials in Table Z-3 are commonly understood to be minerals or mineraldusts. Moreover, the listing for \”inert or nuisance dust\” corroboratesthe firm impression given by the table that organic substances are notincluded within it because organic matter is not chemicallyinert.[[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 nuisancedust\” should, in contrast with the other dusts regulated by Table Z-3,be interpreted in accordance with a \”common understanding\” by industrialhygienists and the grain-handling industry that it includes vegetabledusts. The Secretary apparently would have us ignore the fact that theother provisions of the standard apply only to mineral dusts. However,we adhere to the principle that the provisions of a standard should beinterpreted in the context of the entire standard. _See State HighwayCommission 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 ratherin the context of the whole act). _See_ _generally_, 2A _SutherlandStatutory_ _Construction_ ? 46.05 (4th ed. 1984).In any event, even if we consider the inert or nuisance dust provisionin isolation, we are not convinced that the term \”inert or nuisancedust\” has a special meaning that is commonly understood within theindustrial hygiene profession and the grain-handling industry. TheSecretary’s assertion of a common understanding in the industrialhygiene profession is contradicted by the record evidence. IH Gribbleand Dr. Richard testified in support of the Secretary’s interpretation. However, the documentary evidence establishes that OSHA Deputy Directorfor Federal Compliance and State Programs Wilson, OSHA AssistantRegional Administrator Holder, and \”Herbert Stokinger of the A.C.G.I.H.TLV Committee\” all agreed with Bunge’s interpretation. Thus, industrialhygienists obviously disagree on the meaning of the provision.The record also contains no support for the assertion that thegrain-handling industry understands that grain dusts are included withinthe terms ”inert, or nuisance dust.\” Judging from the testimony of thewitnesses, the term \”nuisance dust\” appears to be meaningless to anyonewho is not an industrial hygienist. As for the term \”inert dust,\” ithas two very distinct meanings rather than a single, commonly understoodmeaning. The record shows that industrial hygienists are alone in theirunderstanding that this term refers to biological inertness. Thewitnesses who were not industrial hygienists understood this term asreferring to chemical inertness and, thus, because grain dusts are notchemically inert, the standard would apparently exclude rather thaninclude 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 anawareness within the grain-handling industry of the publicitysurrounding the Secretary’s attempts to regulate grain dust under theinert or nuisance dust provision of the mineral dust standard.[[16]] However, the Constitution requires fair notice of the requirements ofthe law, not fair notice of an agency’s enforcement position.Moreover, adoption of the Secretary’s interpretation of the inert ornuisance dust provision would deprive the grain handlers of their dueprocess right to fair notice of the standard’s requirements. TheSecretary’s position conflicts with the principle of regulatoryconstruction that standards are not to be construed in a way thatdeprives employers of fair notice. _See_ _Diamond Roofing Co. v_._OSHRC_, 528 F.2d 645 (5th Cir. 1976). _Cf_. _Marshall v. AnacondaCo_., 596 F.2d 370 (9th Cir. 1979) (court rejects interpretation of ?1910.179 (b)(2) that raises \”serious question(s) regarding itsvalidity\”). As our discussion above indicates, there is nothing in themineral dust standard generally, or in the inert or nuisance dustprovision in particular, that places employers on notice that thestandard applies to grain dust. On the contrary, the manner in whichthe Secretary adopted the mineral dust standard deprived employers ofany notice they might otherwise have been given.In the process of developing the mineral dust standard, the Secretarydid not give even indirect notice of an intent to govern vegetabledusts. When the ACGIH adopted its version of Table Z-3, it accompaniedits listings with explanatory materials indicating that at least one setof TLV’s, for \”‘Inert’ or Nuisance Particulates,\” applied to bothmineral and vegetable dusts. See note 11 _supra_. But when theSecretary incorporated these TLV’s into 41 C.F.R. ? 50-204.50, see note10 _supra_, he did not incorporate the ACGIH’s list of examples and itsdefinitional sections. Moreover, when the Secretary later adopted theWalsh-Healey standard as an established Federal standard under section6(a) of the Act and repromulgated it as an OSHA standard, he eliminatedany reference to the ACGIH and its TLV’s as the indirect source of theOSHA standard. As a result, there is absolutely nothing in the OSHAstandard to indicate that any of its provisions apply to organic dusts. The mineral dust standard contains no definition of the terms \”inert ornuisance dust,\” no list of examples, and no other clarifyinginformation.[[17]]The Secretary nevertheless maintains that we should construe the mineraldust standard to effectuate the intent of the ACGIH. Deference to theintent of the ACGIH is not proper here, however, because there wasnothing to give the public notice that the ACGIH’s intent was carriedover when the Secretary adopted the standard. It is axiomatic that OSHAstandards must be interpreted in accordance with the natural and plainmeaning of their words; they cannot be construed to mean what the agencymay have intended but did not adequately express. _Diamond Roofing Co.v. OSHRC_, 528 F.2d at 649. _See_ _also_ _Bechtel Power Corp._, 85OSAHRC , 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 notsay\”). Adoption of a strained interpretation of the mineral duststandard, an interpretation that bears no reasonable relationship to thestandard’s plain words, would not serve the purposes of the Act becausethe standard would not be effective in guiding the conduct ofemployers. _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, 1984CCH OSHD ? 26,924 at p. 34,500 (No. 80-97, 1984). We therefore rejectthe Secretary’s interpretation of the mineral dust standard andinterpret that standard in accordance with its plain meaning.IIAAs noted previously, in Docket No. 77-1622 the Secretary also allegedthat Bunge’s failure to reduce airborne levels of soybean dust on thefourth floor bin deck and the shipping gallery violated the crystallinequartz silica provision of the mineral dust standard. The judgeaffirmed this alternative allegation without expressly discussing thescope of the crystalline quartz silica provision. However, the judgeimplicitly adopted the interpretation that was set forth in thetestimony of IH Gribble and Dr. Thomas A. Richard, the Secretary’s twoexpert witnesses in the field of industrial hygiene.According to these witnesses, OSHA does not have a PEL for purecrystalline quartz silica,[[18]] but rather, the PEL’s established inTable Z-3 govern all silica-bearing dusts, that is, any dust thatincludes crystalline quartz silica as one of its components.Accordingly, these witnesses reasoned, the crystalline quartz silicaprovision applies to the soybean dust at Bunge’s workplace because thatdust contained quartz.The witnesses also testified that the PEL’s for inert or nuisance dustand for crystalline quartz silica are interrelated. If the number 0(representing dust with no quartz in it) is inserted into thecrystalline quartz silica formulas, the result is the PEL’s for inert ornuisance 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 ofPEL’s depending on the percentage of the total dust or the totalrespirable fraction of the dust that is crystalline quartz silica. Inthis way, the PEL’s are lowered as the percentage of the silica in thedust becomes higher. The upper limit of the sliding scale is the PELfor inert or nuisance dust (containing no quartz); the lower limit isthe PEL for pure quartz dust.IH Gribble further illustrated the operation of the crystalline quartzsilica provision by describing how he arrived at his conclusion that thePEL’s for crystalline quartz silica at Bunge’s workplace on April 27 hadbeen exceeded. As explained in Part IA _supra_, approximately twomonths after Gribble obtained the three air contaminant samples duringhis inspection of Bunge’s grain elevator, the samples were transmittedfrom OSHA’s New Orleans Area Office to OSHA’s testing laboratory in SaltLake City. There, lab chemist John C. Germ conducted an x-raydiffraction analysis on the samples. Based on his analysis, Germconcluded that each sample contained crystalline quartz silica. Thex-ray diffraction analysis also resulted in a quantitative determinationas to the amount of quartz in each of three samples. Specifically, Germdetermined the amount of crystalline quartz silica as a percentage ofthe total weight of the dust collected on the filter. He recorded thefollowing quantitative results:Filter 030 (shipping gallery, total dust) 2.4% quartzFilter 044 (bin deck, respirable dust) 3.5% quartzFilter 051 (bin deck, total dust) 4.6% quartzAt the hearing, Germ acknowledged that x-ray diffraction analysis shouldnot be used to analyze total dust samples. On the standardized forms onwhich he had recorded his analytical results, printed in such a mannerthat it cannot be overlooked, was the following notation:OSHA X-ray Si02 Procedure. This X-ray analysis is accurate only forrespirable samples of (less than 10 micrograms) diameter. Nonrespirablesamples should be analyzed colorimetrically by P & CAM 106.Shown this standardized notation, Germ did not deny that x-raydiffraction analysis was considered by OSHA itself to be an inaccuratemethod of analyzing total dust samples.[[19]] Instead, he testified tothe effect that he had relied on the results of his analysis of thetotal dust samples only to corroborate the results of his analysis ofthe respirable dust sample (filter 044).Nevertheless, IH Gribble used these results to compute the PEL’s forboth respirable crystalline quartz silica and total crystalline quartzsilica at Bunge’s workplace on April 27. First, Gribble looked to thetwo formulas in Table Z-3 that are used to determine the PEL’s forrespirable crystalline quartz silica and for total crystalline quartzsilica. According to the witness, the notations \”% Si02\” and \”% S202\”(apparently a typographical error) refer to the percentage by weight ofthe total dust collected (i.e., either all dust in the employee’sbreathing zone or all respirable dust) that is crystalline quartzsilica. Here, these were the figures supplied by lab chemist Germ,i.e., 2.4%, 3.5%, and 4.6%. Using these figures, Gribble calculated thecontrolling PEL’S.[[20]] Gribble’s next step was to compare eachemployee’s 8-hour time weighted average (TWA) exposure with thatemployee’s corresponding PEL. According to Gribble, the relevantexposure for purposes of this comparison was the previously-determined8-hour TWA exposure for either all dust or all respirable dust in theemployee’s breathing zone, which in this case measured the amounts ofsoybean dust (total or respirable) to which the three employees at issuewere exposed on April 27. Upon making these comparisons, Gribbleconcluded that in each instance the applicable PEL had been exceeded.[[21]]In his decision, Judge Oringer credited the Secretary’s evidence on themeaning of the crystalline quartz silica provision and the percentage ofquartz in the Bunge samples. He found that all three of the Bungeemployees whose exposures were sampled had been exposed to levels ofquartz-bearing dust in excess of the mineral dust standard’s PEL’s fortotal and respirable crystalline quartz silica. He also found thatBunge had failed to implement feasible engineering controls to reducethe dust levels within permissible limits. Accordingly, he sustainedthe Secretary’s alternative charge under the crystalline quartz silicaprovision of the mineral dust standard.On review, Bunge argues that the judge erred in affirming the allegedviolation of the crystalline quartz silica provision. Bunge suggeststhat the judge’s interpretation and application of this provision mayhave been erroneous. In any event, it contends that the provisioncannot be interpreted and applied as the Secretary and the judge havedone without depriving grain handlers of their due process rights tofair notice of the standard’s requirements.Bunge raises two fair notice issues in support of its claim that \”thisvirtually indecipherable regulation does not pass constitutionalmuster.\” First, it argues that the provision is unenforceably vaguebecause the employer cannot tell whether it is in compliance with theregulation. Bunge notes Gribble’s testimony concerning his calculationsof over-exposure and asserts that there is nothing in the mineral duststandard or its crystalline quartz silica provision that gives noticethat the PEL, once calculated, should be compared with the 8-hour TWAexposure for all of the dust collected in the sample, including both theorganic and inorganic components of the dust.The second fair notice issue is related to st it is error to treat it asnuisance dust when considering a [crystalline quartz] silica violation.\”BWe have already concluded that the mineral dust standard applies only tomineral dusts. Because it is undisputed that soybean dust is not amineral dust, the crystalline quartz silica provision of the mineraldust 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 tworelated provisions of single standard must be interpreted in the contextof the standard as a whole. _See_ _State Highway Commission of Missouriv. Volpe_; _2A Sutherland Statutory Construction_ ? 46.05. It would beinconsistent for us to hold that the inert or nuisance dust provisiondoes not apply to soybean dust, while the crystalline quartz silicaprovision of the same table does apply to soybean dust. Bunge cites tothe testimony of the Secretary’s witnesses that the PEL’s for inert ornuisance dust and for crystalline quartz silica, as they are interpretedby the Secretary, are in effect PEL’s for nuisance dust containingquartz. Therefore, since the PEL’s for inert or nuisance dust do notapply to soybean dust, the formulas for reducing those PEL’s when quartzis present in the dust also do not apply.We find considerable merit in Bunge’s analysis. However, we alsoobserve another fundamental inconsistency in attempting to apply thecrystalline quartz silica provision to grain dust. We vacate thenuisance dust allegation on ground that the inert or nuisance dust PEL’sare set forth in a table that applies only to mineral dusts. Thecrystalline quartz silica PEL’s are included in the same table, TableZ-3. The mineral dust standard does not give fair notice that its inertor nuisance dust provision applies to a dust that is predominantlyorganic. We find the same notice problem in applying a differentprovision of the same standard to the same dust. Since Table Z-3 islimited in its coverage to mineral dusts, we conclude that _none_ of theprovisions of the mineral dust standard can be applied to soybean dust.We also agree with Bunge’s argument that the Secretary’s interpretationof the crystalline quartz silica provision deprives grain handlers oftheir 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 understandingthat the crystalline quartz silica PEL’s are applicable to grain dust. Certainly, the Secretary cannot rely on any publicity surrounding hisenforcement position, for this appears to be the first and only effortto apply this provision to this type of dust.[[22]] In fact, we areunaware of any other enforcement action where the Secretary sought toapply the crystalline quartz silica provision to a dust that was notwholly, or at least predominantly, silica dust. Nor is there anylegislative history to support the Secretary’s interpretation of thisprovision. The _1968_ _ACGIH-TLV’s_ pamphlet, which is the sourcedocument, provides no more guidance on the meaning and application ofthe crystalline quartz silica provision than does the OSHA mineral duststandard itself. Neither the standard, the source document, nor anyother written materials that we are aware of explains the Secretary’sinterpretation and application of the provision. Indeed, our onlyinformation on these matters is the testimony of IH Gribble and Dr. Richard.We are left then with the language of the standard, which Bungecorrectly characterizes as \”virtually indecipherable.\” The standardstates that \”exposure to any material listed in Table Z-3\” shall notexceed 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 islisted is captioned \”Mineral Dusts.\” To begin with, we could notreasonably expect that an employer looking through the Secretary’sstandards to find the PEL’s for grain dust would read the table andconclude that it had found the applicable PEL’s.Even if the employer made it over this initial hurdle, it would haveconsiderable difficulty in determining whether it had exceeded thePEL’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 atypographical error or do they refer to two different substances? Dothey refer to all silica in the sample or just the silica that iscrystalline quartz? The employer would then have to decide whether tostate the percentages as whole numbers (as the witnesses did) or astheir decimal equivalents (as is more common in performing mathematicalcomputations). Finally, once the employer calculated the PEL’s, itwould have to recognize that, contrary to the language of the standard,those PEL’s do not govern the amounts of total quartz or respirablequartz in the air but rather the amounts of total dust or respirabledust, including both the organic and inorganic components of the dust. In view of these many uncertainties and ambiguities, we conclude that areasonable employer in the grain-handling industry would not understandfrom reading the crystalline quartz silica provision of the mineral duststandard that it is to be interpreted and applied in the mannerdescribed by the Secretary’s witnesses. The provision as applied to thefacts of this case does not give fair notice of its requirements.[[23]]IIIThe separate citations in Docket Nos. 78-0838 and 78-2213 allegeviolations of 29 C.F.R. ?? 1910.1000(c) and (e), based on the provisionof section 1910.1000 that has been referred to throughout this decisionas \”the inert or nuisance dust provision\” of the \”mineral duststandard.\” Neither case involves any allegation under the crystallinequartz silica provision of the mineral dust standard.[[24]] No hearinghas been held in either case. Instead, the Secretary and Bunge enteredinto stipulated settlement agreements. The two agreements areessentially identical. The key provision of both agreements, as it isstated in the agreement filed in Docket No. 78-0838, provides:Whereas each of the parties herein have spent a substantial amount inthe preparation and trial of OSHRC Docket No. 77-1622 . . . ; andwhereas the identical issue is presented herein; the parties thereforestipulate and agree to be bound by the highest decision rendered inOSHRC Docket No. 77-1622, whether by the Occupational Safety and HealthReview Commission, the United States Court of Appeals, or the UnitedStates Supreme Court, so that if grain dust ultimately is held to be anuisance dust . . . within the meaning of . . . Table Z-3……, thismatter shall be heard on the merits, and if grain dust ultimately is notheld to be a nuisance dust . . . . this matter shall be dismissed.After issuing his decision in Docket No. 77-1622, Judge Oringer issuedseparate decisions in Docket Nos. 78-0838 and 78-2213. In both of thesecases, he concluded that the issues were ripe for decision. Accordingly, he applied his holding in Docket No. 77-1622 and vacatedthe citation items in the two later cases on the ground that the inertor nuisance dust provision does not apply to employee exposure to graindust. On review, the Secretary argues, and Bunge agrees, that the judgeacted prematurely in vacating in citation items at issue in Docket Nos.78-0838 and 78-2213. The parties contend that the judge erred infailing 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 removethese two cases from this docket. In addition, the parties have notbeen prejudiced as a result of the judge’s action. By deciding thesethree cases as a consolidated unit, we have accomplished the result theparties sought to achieve through their settlement agreement. The inertor nuisance dust provision has been uniformly applied in all threecases, and all three cases remain open if our decision is appealed.Accordingly, we review the merits of the judge’s rulings on thecontested citation items in Docket Nos. 78-0838 and 78-2213. For thereasons stated previously, we agree with the judge that the citationitems must be vacated because inert or nuisance dust provision of themineral dust standard does not apply to employee exposure to grain dust.IVIn Docket No. 77-1622, the judge’s decision is affirmed with respect tothe allegations under the inert or nuisance dust provision and reversedwith respect to the allegations under the crystalline quartz silicaprovision. In Docket Nos. 78-0838 and 78-2213, the judge’s decisionsare affirmed. All citation items at issue on review in thisconsolidated proceeding, including alternative allegations, are vacated.FOR THE COMMISSIONRay H. Darling, Jr.Executive SecretaryDated: April 22, 1986————————————————————————The Administrative Law Judge decision in this matter is unavailable inthis format. To obtain a copy of this document, please request one fromour Public Information Office by e-mail ( [email protected] ), telephone (202-606-5398), fax(202-606-5050), TTY (202-606-5386).FOOTNOTES:[[1]] The term \”mineral dust standard\” will be used throughout thisdecision to refer to various related provisions of 29 C.F.R. ?1910.1000that, taken together, require employers to implement protective measureswhenever their employees are exposed to mineral dust levels that exceedany of the permissible exposure limits (\”PEL’s\”) listed in Table Z-3 of?1910.1000. \”Inert or nuisance dust\” is one of the listed substancesthat is regulated under the mineral dust standard. The pertinentprovisions 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-3of this section shall be limited in accordance with the requirements ofthe following paragraphs of this section.(c) Table Z-3: An employee’s exposure to any material listed in TableZ-3, in any 8-hour work shift of a 40-hour work week, shall not exceedthe 8-hour time weighted average limit given for that material in the table.TABLE Z-3 — MINERAL DUSTSSubstance \t\t Mg\/M3Inert or Nuisance Dust:Respirable fraction …………5mg\/M3Total dust …………………….15mg\/M3(e) To achieve compliance with paragraph (a) through (d) of thissection, administrative or engineering controls must first be determinedand implemented whenever feasible. When such controls are not feasibleto achieve full compliance, protective equipment or any other protectivemeasures shall be used to keep the exposure of employees to aircontaminants 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 regulatedunder the \”mineral dust standard.\” In addition to containing the PEL’sfor \”inert or nuisance dust,\” Table Z-3 of ? 1910.1000 also sets forththe following PEL’s for \”crystalline quartz silica\”:TABLE Z-3 — MINERAL DUSTSSubstance \t* \tMg\/M3Silica:Crystalline: \t\t10 mg\/M3Quartz (respirable) ……… \t* \t% SiO2 + 2Quartz (total dust) ………. \t* \t30 mg\/M3% S2O2 [sic] + 2[[3]] Bunge presents three challenges to the propriety of theSecretary’s enforcement procedures in Docket No. 77-1622. First, itargues that, contrary to the requirements of ? 8(a)(2) of the Act, 29U.S.C. ? 657(a)(2), the underlying inspection was not conducted \”withinreasonable limits and in a reasonable manner.\” More specifically, itcontends that the inspection was unreasonable because the aircontaminant samples taken by the Secretary were obtained underconditions that were not representative of the conditions that usuallyexisted at its workplace. Bunge also argues that the judge erred ingranting two motions by the Secretary to amend the allegations ofviolation contained in the citation. Finally, Bunge charges that,during the period between the filing of its notice of contest and thebeginning of the hearing, the Secretary engaged in a series ofmisrepresentations and abuses of procedure that in combination\”subverted the Act’s fundamental process.\” According to Bunge, theSecretary thereby deprived it of the administrative and procedural dueprocess 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, whichare 10 microns or less in length. This size separation occurs when adevice called a \”cyclone\” is used in conjunction with the sampling device.[[5]] The samples were taken in the breathing zones of three Bungeemployees. A sampling device containing a filter was placed on LionelMcZeal while he worked on the shipping gallery. The filter collected5.81 mg of total dust. Using this figure in conjunction with otherrelevant data, IH Gribble calculated McZeal’s 8-hour time weightedaverage (TWA) exposure to be 8.06 mg\/M3. McZeal’s exposure was thereforewithin 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 secondsampling device with a cyclone attached so that only respirable dustwould be collected was placed on Rickie Cure as he worked on the fourthfloor 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 ornuisance dust. The third sampling device was placed on Joseph Charleswhile he worked on the fourth floor bin deck. The filter collected18.94 mg of dust (total dust). The 8-hour TWA exposure for Charles wascalculated to be 26.05 mg\/M3. This exposure exceeded the 15 mg\/M3 PELfor total inert or nuisance dust.[[6]] The Secretary charged a violation of the mineral dust standard onthe shipping gallery based solely on the sampling of McZeal’s exposure,which did not establish a violation of the inert of nuisance dustprovision of the cited standard. See note 5 _supra_. There is noexplanation in the record for this anomaly.[[7]] The third and final lab analysis was conducted several monthslater, apparently for the purpose of reconciling the conflict betweenthe first two analyses. On November 15, lab chemist Dixon conducted asecond petrographic analysis on one of the samples. This analysisconfirmed Germ’s report that crystalline quartz silica was present inthe sample. Dixon was unable to make a quantitative determination. Atthe hearing, Dixon testified that various treatments of the samplebetween June 27 and November 15 had removed almost all of the materialon the filter \”and just about everything I saw at that point wasquartz.\” Dixon hypothesized that the crystalline quartz silica he sawon November 15 had been in the sample all along, but that he had beenunable to see it on June 27 because of the \”interference\” of an organic\”coating.\” In his opinion, when this coating was removed, primarilythrough \”chemical ashing\” (treatment with phosphoric acid), he was ableto see the quartz and confirm its presence in the sample.[[8]] The \”A.C.G.I.H.\” is the American Conference of GovernmentalIndustrial Hygienists. As discussed more fully _infra_, its \”TLVCommittee\” drafted the standard that was the indirect source of themineral dust standard. It appears from the source document that\”Herbert E. Stokinger, Ph.D.,\” was the chairman of the committee thatdrafted the standard. See Exh. J-1 (for judicial notice) at page 26. In addition, a second ACGIH publication introduced into the record asExh. J-2 (for judicial notice) lists \”Herbert E. Stokinger, Ph.D.\” as amember of the \”1977 TLV Airborne Contaminants Committee.\” The recorddoes not otherwise identify Stokinger or elaborate on the telephoneconversation with him.[[9]] On February 2, 1978, approximately three weeks before the hearingin Docket No. 77-1622, OSHA issued Program Directive #300-11, whichexpressly cancelled the July 13 Wilson-Tice memo. In this document,which was signed by the same Deputy Director Wilson, OSHA interpretedthe Table Z-3 PEL’s for inert or nuisance dust as applying to all typesof nuisance dust, both organic and mineral, and as specificallyincluding 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 wasa standard originally issued under the Walsh-Healey Act and lateradopted as an \”established Federal standard\” under ? 6(a), 29 U.S.C. ?655(a), of the Occupational Safety and Health Act. In turn, theWalsh-Healey standard was largely based on a non-governmental consensusstandard developed by the ACGIH (American Conference of GovernmentalIndustrial Hygienists). In particular, the mineral dust PEL’sestablished under 41 C.F.R. ? 50-204.50 (and later published in TableZ-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 \”permissibleexposure limit (PEL)\” are often used interchangeably. However, there isa difference in their meaning. As stated in the preface to the _1968ACGIH-TLV’s_ pamphlet, a TLV is an airborne concentration of a substancethat represents the level at \”which it is believed that nearly allworkers may be repeatedly exposed, day after day, without adverseeffect.\” The nature of this adverse effect \”may differ from substanceto substance; protection against impairment of health may be the guidingfactor 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 industrialexperience, from experimental human and animal studies, and whenpossible, from a combination of the three.\”Thus, \”TLV\” is an industrial hygienist’s term and, as the ACGIHexplained, the limits \”are intended for use in the field of industrialhygiene.\” In contrast, \”PEL\” is a legal term referring to a limit thatmay not be exceeded or a limit that triggers certain legal obligationswhen it is exceeded. When the Secretary of Labor incorporated theTLV’s developed by the ACGIH into his occupational health standards, hethereby transformed the TLV’s into legally enforceable PEL’s.[[11]] The _1968 ACGIH-TLV’s_ pamphlet refers to \”‘Inert’ or NuisanceParticulates\” and sets forth a list of \”Some ‘Inert’ or NuisanceParticulates\” in its appendix. The list includes both organic andinorganic substances and both mineral and vegetable dusts. For example,four of the components of grain dust are included on the list–calciumcarbonate, cellulose, starch and sucrose. However, neither grain dustgenerically nor any particular type of grain dust is included on thelist. The pamphlet also contains a section in the preface that explainsthe terms \”‘Inert’ or Nuisance Particulates.\” This section similarlyrefers to both organic and inorganic substances as examples. TheSecretary also introduced into the record the 1977 version of the ACGIHpamphlet, which was the most recent version at the time of hearing. That pamphlet similarly includes a list of particulates and anexplanatory section that indicate an intent to include organic dustswithin the coverage of the TLV’s.[[12]] The same rules of interpretation are applicable in interpretingboth statutes and administrative regulations, such as the Secretary’soccupational safety and health standards. _See_, _e.g_., _Ohio-SealyMattress 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 expertwitness 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 andtherefore not classified scientifically as a mineral. Amorphous silicaincludes two subcategories–diatomaceous earth and dehydrated silicagel. 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\”. Quartzis the most common of these substances, not only in nature but also inoccupational environments.[[14]] Lab chemist Dixon stated that three of the substances listed inTable Z-3 are not classified scientifically as \”minerals\”: amorphoussilica because it is not crystalline, Portland cement (a silicate)because it does not occur in nature, and coal dust because coal isorganic. We assume that this testimony accurately describes how amineralogist would classify the substances. Nevertheless, it is clearon this record that all of the substances in Table Z-3 are considered tobe \”mineral dusts\” under the common usage of the term \”mineral.\” Eventhe Secretary’s witnesses admitted this fact. For example, IH Gribbletestified that all of the Table Z-3 substances are mineral dusts withthe exception of coal dust. Even coal, he conceded, is \”termed by manyto be a mineral because it’s mined from the ground.\” Dr. Richard gavesimilar testimony. With respect to coal dust, he stated that coal isconsidered to be a \”natural mineral deposit\” despite its organiccomposition.[[15]] At the hearing, Dr. Thomas J. Culpepper, a witness for Bunge whowas found to be an expert in environmental analytical chemistry,testified that the term \”inert\” to a chemist means nonreactive. Forthis reason, he concluded that organic dusts such as grain dusts wouldnot be classified as inert or nuisance dusts.[[16]] The Secretary introduced various exhibits, as well as thetestimony of industrial hygienist Gribble and Dr. Richard, showing that,prior to the instant citation against Bunge, both federal and stateofficials had issued citations to several grain handlers for dust levelsexceeding the inert or nuisance dust PEL’s. The Secretary also provedthat his enforcement actions had been publicized both in trade journalsand in a magazine published by OSHA. In his brief to the Commission,the Secretary cites this evidence as proving that the term \”nuisancedust\” is commonly understood within the grain-handling industry asincluding grain dust. He cites no other evidence in support of thatproposition.[[17]] We further observe that, even if an employer were aware of thestandard’s ACGIH precursors, it would be very difficult for him todiscover the intent of the ACGIH in developing its TLV’s for inert ornuisance dust. At the hearing, IH Gribble testified that it had beendifficult for him–a professional industrial hygienist and a member ofthe ACGIH–to obtain a copy of the 1968 pamphlet so that he could reviewthe ACGIH’s explanatory sections. Certainly today it would be even moredifficult for an employer engaged in grain handling to obtain a copy. Under these circumstances, it would be unreasonable to expect employersto refer to source materials, and especially these ACGIH sourcematerials, outside of the OSHA standard itself in order to give to thestandard’s terms a meaning that is contrary to their commonly understoodmeaning.[[18]] According to the witnesses, PEL’s for pure crystalline quartzsilica 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 standardapplied to grain dust containing silica, we could not sustain thecitation with respect to the allegation that total dust levels exceededthe PEL’s for crystalline quartz silica, since those allegations restsolely on Germs X-ray diffraction analysis of filters 030 and 051.[[20]] Gribble further testified that the formulas refer to whole numberpercentages rather than their decimal equivalents, e.g., 2.4 rather than.024. Thus, Gribble inserted the number 3.5 into the respirable dustformula to obtain a respirable dust PEL of 1.81 mg\/M3 for the fourthfloor bin deck. He inserted the numbers 2.4 and 4.6 into the total dustformula to obtain total dust PEL’s of 6.82 mg\/M3 and 4.54 mg\/M3 for theshipping gallery and the fourth floor bin deck, respectively.[[21]] At the hearing, Gribble in effect conceded that no charge shouldhave been made with respect to crystalline quartz silica on the shippinggallery. Gribble referred to guidelines set forth in an OSHA IndustrialHygiene Manual, although he did not state which edition of the manual orwhich section he was referring to. Under those guidelines, as describedby the witness, once he had determined the applicable PEL, he shouldthen have adjusted it by multiplying the PEL by the \”statisticalcorrection factor.\” This adjustment is made to take into account thepossibility of error in the collection of the sample and in thelaboratory determination of the percentage of crystalline quartzsilica. It accomplishes this goal by increasing the PEL to add in amargin of error. Gribble also testified that, for a total dust sample,the statistical correction factor was 1.25. Thus, the adjusted PEL fortotal 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 8.06mg\/M3, exposure to excessive dust levels was not established under theSecretary’s internal guidelines.[[22]] At the hearing, the Secretary’s counsel stated that, to the bestof his knowledge, this was the first time a granary had ever beencharged with a violation of this provision. In addition, the two labchemists who analyzed the Bunge samples indicated that they wereprobably the first grain dust samples the Salt Lake City testinglaboratory had ever analyzed for silica content. While these chemistsfurther testified that similar analyses were conducted after theanalysis of the Bunge samples, we are unaware of any subsequent citationof a grain handler under the crystalline quartz silica provision.[[23]] Indeed, we are not persuaded that the Secretary’s interpretationand application of the crystalline quartz silica provision is consistentwith the intent of the ACGIH, which drafted the source TLV’s. AlthoughIH Gribble and Dr. Richard gave consistent testimony to the effect thatthe PEL’s cover all silica-bearing dusts, neither cited any documentstating that the PEL’s should be applied to predominantly organic dustssuch as grain dust. There is certainly nothing in the ACGIH sourcedocument that supports this conclusion.More importantly, however, we are unable to conclude that application ofthe crystalline quartz silica provision to grain dust would have theeffect intended by the ACGIH. Based on the ACGIH’s explanation of howit develops its TLV’s, it appears likely that the TLV’s for crystallinequartz silica were primarily designed to protect employees from fibroticchanges to the lung, including specifically the risk of contractingsilicosis. Yet, the documentary evidence presented by the Secretarysuggests that it is virtually impossible to contract silicosis throughexposure to grain dust.In particular, we note the epidemiological survey and research studyadmitted 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 casereported in 1944, \”there has been no report in the literature supportingthe possibility that free silica in grain dust might be a factor in theresultant respiratory disease.\” _Williams_ at p. 320. Indeed, theseresearchers unequivocally expressed their opinion that free silica isnot a factor:The dust analyses indicate that most of the free silica is in the soilfraction of the dust. It is known that lifetime exposure to the dust ofdesert sands does not lead to the development of silicosis. Likewise,there is no evidence that the free silica in soil dust can produce thedisease. It is unlikely that the very small amount of free silica inthe organic fraction could produce silicosis. Moreover, the silica isclosely bound physically to the organic material and there is none ofthe crushing or grinding of silicious material which creates a silicosishazard. Therefore . . . there is strong evidence against silica playingany role in the respiratory disease associated with exposure to graindust. Williams at p. 326. In the absence of any reason to believethat the quartz within grain dust creates any hazard whatsoever, wecannot conclude that the Secretary’s interpretation of the crystallinequartz silica provision serves the purpose intended by the ACGIH.[[24]] Also at issue in Docket No. 78-2213 are alleged violations of twosubsections of 29 C.F.R.? 1910.134. Because these requirements areincorporated by reference into the mineral dust standard–specifically,the last sentence of ?1910.1000(e)–the parties agree that they can beapplied to the cited working conditions only if the inert or nuisancedust provision can be applied to those conditions.”