“Docket No. 77-1622_78-0838_78-2213 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 & 78-2213DECISION Before:\u00a0 BUCKLEY, Chairman; RADER and WALL, Commissioners. BY THE COMMISSION:These three consolidated cases are before the Occupational Safety and HealthReview Commission under 29 U.S.C. ? 661(i), section 12(j) of the Occupational Safety andHealth Act of 1970, 29 U.S.C. ?? 651-678 (\”the Act\”).\u00a0 The Commission isan adjudicatory agency, independent of the Department of Labor and the Occupational Safetyand Health Administration (\”OSHA\”).\u00a0 It was established to resolve disputesarising out of enforcement actions brought by the Secretary of Labor under the Act and hasno regulatory functions.\u00a0 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, 29C.F.R. ? 2200.9. because they involve common parties and common questions of law andfact.\u00a0 Bunge Corporation (\”Bunge\”) is one of the largest employers withinthe international grain-handling industry.\u00a0 As a result of separate inspections ofits facilities in Destrehan, Louisiana (Docket No. 77-1622), Galveston, Texas (No.78-0838), and Osceola, Arkansas (No. 78-2213), Bunge was issued citations allegingviolations of the inert or nuisance dust provision of the mineral dust standard at allthree of these workplaces.[[1]]\u00a0 The principal issue on review is whetherAdministrative Law Judge David G. Oringer erred in vacating these citations on the groundthat the inert or nuisance dust provision does not apply to grain dust.\u00a0 Also onreview, 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 the judge’s rejection ofvarious procedural defenses.[[3]]We conclude that neither the inert or nuisance dust provision nor the crystallinequartz silica provision of the mineral dust standard can be applied to regulate employeeexposure to grain dust.\u00a0 On this ground, we vacate each of the citation items onreview.\u00a0 In light of our disposition, we need not reach the procedural issues raisedby Bunge in Docket No. 77-1622.IAOn March 4, 1977, OSHA began an inspection of Bunge’s marine terminal grainelevator at its export port facility in Destrehan, Louisiana.\u00a0 The citation at issuein Docket No. 77-1622 is based on three air contaminant samples taken by industrialhygienist (\”IH\”) William D. Gribble during that inspection.\u00a0 Two total dustsamples and one respirable dust sample were obtained on April 27.[[4]]\u00a0 The recordestablishes, and the parties agree, that the dust collected in these samples was soybeandust, which is a type of grain dust.[[5]]As a result of its inspection, OSHA issued a citation to Bunge alleging violations of 29C.F.R. ?? 1910.1000 (c) and (e).\u00a0 See note 1 supra.\u00a0 The citationalleged that employees on the fourth floor bin deck and on the shipping gallery wereexposed on April 27 to levels of dust that exceeded the mineral dust standard’spermissible exposure limits for respirable inert or nuisance dust and for total inert ornuisance dust.[[6]]\u00a0 The citation further alleged that Bunge failed to determine andimplement feasible administrative or engineering controls to reduce those dust levelswithin permissible limits.Bunge contested the citation and, in its notice of contest, requested an informalconference with OSHA.\u00a0 At this conference, Bunge argued that the inert or nuisancedust provision does not apply to the cited conditions because Table Z-3 applies only tomineral dusts, and grain dust is not a mineral dust.\u00a0 OSHA’s representativesindicated that they would take Bunge’s contentions under advisement.Two days later, the Secretary obtained an extension of time to file the complaintin Docket No. 77-1622.\u00a0 This additional time was used for two purposes–to obtain alaboratory analysis of the three dust samples collected on April 27 and to consult withOSHA’s national office on the legal and policy questions raised by Bunge about the scopeof the standard.On June 20, the Bunge air contaminant samples were transmitted from OSHA’s NewOrleans Area Office to OSHA’s testing laboratory in Salt Lake City.\u00a0 The lab wasasked to determine if there was any mineral content in the samples.\u00a0 Three separateanalyses were conducted for this purpose.\u00a0 On June 27, lab chemist Willard C. Dixonconducted a petrographic analysis, which is essentially no more than a visual examinationthrough a microscope using polarized light.\u00a0 Dixon saw only organic materials in thethree samples.\u00a0 He saw no particles of crystalline quartz silica or any othermineral.\u00a0 He reported to his supervisor that his analysis \”yielded 100% soybeandust.\”On July 8, lab chemist John C. Germ conducted an x-ray diffraction analysis on thesamples.\u00a0 The purpose of this far more sophisticated analysis was to determinewhether two specific substances–crystalline quartz silica and cristobalite–were presentin the samples.\u00a0 Based on his analysis, Germ concluded that the samples did notcontain cristobalite, but did contain crystalline quartz silica.\u00a0 The quartz contentof each sample was calculated to be less than 5% by weight of all the dust collected.\u00a0On July 11, Germ reported his results to the New Orleans Area Office.\u00a0 Usingthese results, IH Gribble computed the PEL’s for crystalline quartz silica at Bunge’sworkplace and concluded that these PEL’s had been exceeded.[[7]]During the same time period that the Secretary’s representatives were awaiting the resultsof the laboratory analysis, they also sought to resolve Bunge’s contention that the inertor 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 turnsought a determination at the national level. Thus, on June 30, a memorandum (\”theHolder memo\”) was sent from an official in the Dallas Regional Office (Holder) to theOffice of Field Coordination, a branch of the national OSHA office.\u00a0 The nationaloffice was informed that the question of whether the inert or nuisance dust provisionapplies to soybean dust had been raised as an issue in a contested case.\u00a0 It was alsoinformed of a \”telephone discussion with Herbert Stokinger of the A.C.G.I.H. TLVCommittee who agrees that only those substances containing mineral dust should be citedunder Table Z-3.\”[[8]]On July 13, the OSHA national office responded by sending a memorandum (\”theWilson-Tice memo\”) from the Deputy Director for Federal Compliance and State Programs(Wilson) to the Dallas Regional Administrator (Tice). The OSHA Deputy Director concludedthat 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 avegetable 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 labchemist Germ’s report on the quartz content of the three samples and the Wilson-Tice memoon the inapplicability of the cited provision, the Secretary’s counsel filed the delayedcomplaint in Docket No. 77-1622.\u00a0 The complaint continued to allege noncompliancewith the mineral dust standard based on Bunge’s failure to implement feasibleadministrative or engineering controls to reduce excessive dust levels within permissiblelimits. The complaint also continued to base the charge of excessive dust levels on thethree air contaminant samples that were taken on the fourth floor bin deck and theshipping gallery on April 27.\u00a0 However, the Secretary sought to amend the citationthrough the complaint to allege that the permissible exposure limits that were exceeded onthat date were the PEL’s for crystalline quarts silica rather than the PEL’s for inert ornuisance dust.\u00a0 Several weeks later, the Secretary moved to amend his pleadings so asto allege in the alternative noncompliance with the inert or nuisance dust provision, withthe crystalline quartz silica provision, or with both provisions of the mineral duststandard.\u00a0 These motions to amend were granted despite Bunge’s objections.\u00a0Accordingly, Docket No. 77-1622 proceeded to a hearing on the merits of the twoalternative charges.BIn his decision in Docket No. 77-1622, Judge Oringer vacated the allegationthat Bunge violated the inert or nuisance dust provision of the mineral dust standard, butaffirmed the alternative allegation that Bunge violated that same standard’s crystallinequartz silica provision.\u00a0 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 be applied toregulate employee exposure to grain dust.\u00a0 In effect, he entered alternateholdings:\u00a0 (a) the provision does not apply to grain dust because it applies only tomineral 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 theconstitutionally required fair notice that it is applicable.\u00a0 Concerning the scope ofthe cited provision, the judge stated:Patently Table Z-3 prohibits excess exposure of employees to mineraldusts.\u00a0 All of the substances listed in Table Z-3 are mineral despite the fact thatcoal may have an organic base.\u00a0 In this cause the only dusts collected were notmineral dust, but soybean dust, an organic non-inert substance.On review, the Secretary argues that the judge erred in vacating the inert ornuisance dust allegation.\u00a0 He argues that the inert or nuisance dust provision shouldbe 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 theprovision’s development, and the history of the provision’s subsequent enforcement as alimitation on both organic and mineral dusts.\u00a0 In elaborating on his \”plainmeaning\” argument, the Secretary contends that the term \”nuisance dust\” hasgenerally and consistently been understood, both in the industrial hygiene profession andin the grain-handling industry, to include vegetable as well as mineral dusts.The Secretary further claims that his enforcement action is consistent with theintent of the ACGIH, the drafters of the inert or nuisance dust TLV’s.[[10]]\u00a0 Heasserts that grain dust is biologically inert in that it normally does not result inirreversible health effects such as scarring of the lungs.\u00a0 He points to provisionsof two ACGIH-TLV’s pamphlets that suggest that such biologically inert dusts are properlyclassified as \”inert or nuisance dust,\” regardless of whether they are vegetableor mineral dusts.[[11]] Accordingly, the Secretary reasons, grain dusts are covered by theOSHA mineral dust standard because they are covered under the source standard.CWe conclude that the mineral dust standard applies only to mineraldusts.\u00a0 Because it is undisputed that soybean dust is not a mineral dust, neither ofthe provisions allegedly violated by Bunge applies to the cited conditions.\u00a0Accordingly, both of the alternative allegations in Docket No. 77-1622 must be vacated.In determining the proper interpretation of the mineral dust standard, we lookprimarily to the language of the standard.\u00a0 \”There is, of course, no morepersuasive evidence of the purpose of a statute than the words by which the legislatureundertook to give expression to its wishes.\”\u00a0 Griffin v. Oceanic Contractors,Inc., 458 U.S. 564, 571 (1982), quoting United States v. American TruckingAssociations, 310 U.S. 534, 543 (1940).[[12]]\u00a0 The standard requires employers tolimit the exposure of their employees within permissible exposure limits whenever theemployees are exposed \”to any material listed in Table Z-3.\”\u00a0 Table Z-3 iscaptioned \”Mineral Dusts\” and includes, in addition to the PEL’s for \”inertor 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, andfor coal dust.[[13]]\u00a0 Bunge argues that the table is limited on its face to mineraldust, and that all of the dusts listed in Table Z-3 are mineral dusts.\u00a0 Although theSecretary attempted to prove that Table Z-3 includes three dusts that are not mineraldusts, the judge found against the Secretary on this factual issue, and we conclude thathis finding is supported by the record.[[14]]\u00a0 We therefore adopt the judge’s findingthat all of the materials in Table Z-3 are commonly understood to be minerals or mineraldusts.\u00a0 Moreover, the listing for \”inert or nuisance dust\” corroborates thefirm impression given by the table that organic substances are not included within itbecause organic matter is not chemically inert.[[15]]\u00a0 In short, the language of thetable, 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 interpretedin accordance with a \”common understanding\” by industrial hygienists and thegrain-handling industry that it includes vegetable dusts.\u00a0 The Secretary apparentlywould have us ignore the fact that the other provisions of the standard apply only tomineral dusts.\u00a0 However, we adhere to the principle that the provisions of a standardshould be interpreted in the context of the entire standard.\u00a0 See State HighwayCommission of Missouri v. Volpe, 479 F.2d 1099, 1111-1112 (8th Cir. 1973) (a sectionof a statute should not be read in isolation but rather in the context of the whole act).\u00a0 See generally, 2A Sutherland Statutory Construction ?46.05 (4th ed. 1984).In any event, even if we consider the inert or nuisance dust provision inisolation, we are not convinced that the term \”inert or nuisance dust\” has aspecial meaning that is commonly understood within the industrial hygiene profession andthe grain-handling industry.\u00a0 The Secretary’s assertion of a common understanding inthe industrial hygiene profession is contradicted by the record evidence.\u00a0 IH Gribbleand Dr. Richard testified in support of the Secretary’s interpretation.\u00a0 However, thedocumentary evidence establishes that OSHA Deputy Director for Federal Compliance andState Programs Wilson, OSHA Assistant Regional Administrator Holder, and \”HerbertStokinger of the A.C.G.I.H. TLV Committee\” all agreed with Bunge’s interpretation.\u00a0Thus, industrial hygienists obviously disagree on the meaning of the provision.The record also contains no support for the assertion that the grain-handlingindustry understands that grain dusts are included within the terms ”inert, or nuisancedust.\”\u00a0 Judging from the testimony of the witnesses, the term \”nuisancedust\” appears to be meaningless to anyone who is not an industrial hygienist.\u00a0As for the term \”inert dust,\” it has two very distinct meanings ratherthan a single, commonly understood meaning.\u00a0 The record shows that industrialhygienists are alone in their understanding that this term refers to biological inertness.\u00a0The witnesses who were not industrial hygienists understood this term as referringto chemical inertness and, thus, because grain dusts are not chemically inert, thestandard would apparently exclude rather than include them. Thus, the Secretary failed toprove that there is any \”common understanding\” in the grain-handling industry ofthe terms \”inert or nuisance dust.\”\u00a0 At most, the Secretary established anawareness within the grain-handling industry of the publicity surrounding the Secretary’sattempts to regulate grain dust under the inert or nuisance dust provision of the mineraldust standard.[[16]]\u00a0 However, the Constitution requires fair notice of therequirements of the law, not fair notice of an agency’s enforcement position.Moreover, adoption of the Secretary’s interpretation of the inert or nuisance dustprovision would deprive the grain handlers of their due process right to fair notice ofthe standard’s requirements.\u00a0 The Secretary’s position conflicts with the principleof regulatory construction that standards are not to be construed in a way that deprivesemployers of fair notice.\u00a0 See Diamond Roofing Co. v. OSHRC, 528F.2d 645 (5th Cir. 1976).\u00a0 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\”).\u00a0 As our discussion aboveindicates, there is nothing in the mineral dust standard generally, or in the inert ornuisance dust provision in particular, that places employers on notice that the standardapplies to grain dust.\u00a0 On the contrary, the manner in which the Secretary adoptedthe mineral dust standard deprived employers of any notice they might otherwise have beengiven.In the process of developing the mineral dust standard, the Secretary did not giveeven indirect notice of an intent to govern vegetable dusts.\u00a0 When the ACGIH adoptedits version of Table Z-3, it accompanied its listings with explanatory materialsindicating that at least one set of TLV’s, for \”‘Inert’ or NuisanceParticulates,\” applied to both mineral and vegetable dusts.\u00a0 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.\u00a0Moreover, when the Secretary later adopted the Walsh-Healey standard as anestablished Federal standard under section 6(a) of the Act and repromulgated it as an OSHAstandard, he eliminated any reference to the ACGIH and its TLV’s as the indirect source ofthe OSHA standard.\u00a0 As a result, there is absolutely nothing in the OSHA standard toindicate that any of its provisions apply to organic dusts.\u00a0 The mineral duststandard contains no definition of the terms \”inert or nuisance dust,\” no listof examples, and no other clarifying information.[[17]]The Secretary nevertheless maintains that we should construe the mineral duststandard to effectuate the intent of the ACGIH. Deference to the intent of the ACGIH isnot proper here, however, because there was nothing to give the public notice that theACGIH’s intent was carried over when the Secretary adopted the standard.\u00a0 It isaxiomatic that OSHA standards must be interpreted in accordance with the natural and plainmeaning of their words; they cannot be construed to mean what the agency may have intendedbut did not adequately express.\u00a0 Diamond Roofing Co. v. OSHRC, 528 F.2d at649.\u00a0 See also Bechtel Power Corp., 85 OSAHRC , 12 BNA OSHC1509, 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 meanwhat it does not say\”).\u00a0 Adoption of a strained interpretation of the mineraldust standard, an interpretation that bears no reasonable relationship to the standard’splain words, would not serve the purposes of the Act because the standard would not beeffective in guiding the conduct of employers.\u00a0 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).\u00a0 We therefore reject theSecretary’s interpretation of the mineral dust standard and interpret that standard inaccordance with its plain meaning.II AAs noted previously, in Docket No. 77-1622 the Secretary also alleged thatBunge’s failure to reduce airborne levels of soybean dust on the fourth floor bin deck andthe shipping gallery violated the crystalline quartz silica provision of the mineral duststandard. \u00a0 The judge affirmed this alternative allegation without expresslydiscussing the scope of the crystalline quartz silica provision.\u00a0 However, the judgeimplicitly adopted the interpretation that was set forth in the testimony of IH Gribbleand Dr. Thomas A. Richard, the Secretary’s two expert witnesses in the field of industrialhygiene.According to these witnesses, OSHA does not have a PEL for pure crystalline quartzsilica,[[18]] but rather, the PEL’s established in Table Z-3 govern all silica-bearingdusts, that is, any dust that includes crystalline quartz silica as one of its components.Accordingly, these witnesses reasoned, the crystalline quartz silica provision applies tothe 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 forcrystalline quartz silica are interrelated.\u00a0 If the number 0 (representing dust withno quartz in it) is inserted into the crystalline quartz silica formulas, the result isthe PEL’s for inert or nuisance dust–15 mg\/m3 for total dust and 5 mg\/m3 for respirabledust.\u00a0 The formulas operate in such a manner as to create a sliding scale of PEL’sdepending on the percentage of the total dust or the total respirable fraction of the dustthat is crystalline quartz silica.\u00a0 In this way, the PEL’s are lowered as thepercentage of the silica in the dust becomes higher.\u00a0 The upper limit of the slidingscale is the PEL for inert or nuisance dust (containing no quartz); the lower limit is thePEL for pure quartz dust.IH Gribble further illustrated the operation of the crystalline quartz silicaprovision by describing how he arrived at his conclusion that the PEL’s for crystallinequartz silica at Bunge’s workplace on April 27 had been exceeded.\u00a0 As explained inPart IA supra, approximately two months after Gribble obtained the three aircontaminant samples during his inspection of Bunge’s grain elevator, the samples weretransmitted from OSHA’s New Orleans Area Office to OSHA’s testing laboratory in Salt LakeCity.\u00a0 There, lab chemist John C. Germ conducted an x-ray diffraction analysis on thesamples.\u00a0 Based on his analysis, Germ concluded that each sample containedcrystalline quartz silica.\u00a0 The x-ray diffraction analysis also resulted in aquantitative determination as to the amount of quartz in each of three samples.\u00a0Specifically, Germ determined the amount of crystalline quartz silica as apercentage of the total weight of the dust collected on the filter.\u00a0 He recorded thefollowing quantitative results:Filter 030 (shipping gallery, total dust)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2.4% quartzFilter 044 (bin deck, respirable dust)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 3.5% quartzFilter 051 (bin deck, total dust)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a04.6% quartzAt the hearing, Germ acknowledged that x-ray diffraction analysis should not beused to analyze total dust samples.\u00a0 On the standardized forms on which he hadrecorded his analytical results, printed in such a manner that it cannot be overlooked,was the following notation:OSHA X-ray Si02 Procedure.\u00a0 This X-ray analysis is accurate only forrespirable samples of (less than 10 micrograms) diameter. Nonrespirable samples should beanalyzed colorimetrically by P & CAM 106.Shown this standardized notation, Germ did not deny that x-ray diffractionanalysis was considered by OSHA itself to be an inaccurate method of analyzing total dustsamples.[[19]]\u00a0 Instead, he testified to the effect that he had relied on the resultsof his analysis of the total dust samples only to corroborate the results of his analysisof the respirable dust sample (filter 044).Nevertheless, IH Gribble used these results to compute the PEL’s for bothrespirable crystalline quartz silica and total crystalline quartz silica at Bunge’sworkplace on April 27.\u00a0 First, Gribble looked to the two formulas in Table Z-3 thatare used to determine the PEL’s for respirable crystalline quartz silica and for totalcrystalline quartz silica.\u00a0 According to the witness, the notations \”%Si02\” and \”% S202\” (apparently a typographical error) refer to thepercentage by weight of the total dust collected (i.e., either all dust in the employee’sbreathing zone or all respirable dust) that is crystalline quartz silica.\u00a0 Here,these were the figures supplied by lab chemist Germ, i.e., 2.4%, 3.5%, and 4.6%.\u00a0Using these figures, Gribble calculated the controlling PEL’S.[[20]] \u00a0Gribble’snext step was to compare each employee’s 8-hour time weighted average (TWA) exposure withthat employee’s corresponding PEL. According to Gribble, the relevant exposure forpurposes of this comparison was the previously-determined 8-hour TWA exposure for eitherall dust or all respirable dust in the employee’s breathing zone, which in this casemeasured the amounts of soybean dust (total or respirable) to which the three employees atissue were exposed on April 27.\u00a0 Upon making these comparisons, Gribble concludedthat in each instance the applicable PEL had been exceeded.[[21]]In his decision, Judge Oringer credited the Secretary’s evidence on the meaning ofthe crystalline quartz silica provision and the percentage of quartz in the Bungesamples.\u00a0 He found that all three of the Bunge employees whose exposures were sampledhad been exposed to levels of quartz-bearing dust in excess of the mineral dust standard’sPEL’s for total and respirable crystalline quartz silica.\u00a0 He also found that Bungehad failed to implement feasible engineering controls to reduce the dust levels withinpermissible limits.\u00a0 Accordingly, he sustained the Secretary’s alternative chargeunder the crystalline quartz silica provision of the mineral dust standard.On review, Bunge argues that the judge erred in affirming the alleged violation ofthe crystalline quartz silica provision.\u00a0 Bunge suggests that the judge’sinterpretation and application of this provision may have been erroneous.\u00a0 In anyevent, it contends that the provision cannot be interpreted and applied as the Secretaryand the judge have done 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 constitutional muster.\” \u00a0First, it argues that the provision is unenforceably vague because the employer cannottell whether it is in compliance with the regulation.\u00a0 Bunge notes Gribble’stestimony concerning his calculations of over-exposure and asserts that there is nothingin the mineral dust standard or its crystalline quartz silica provision that gives noticethat the PEL, once calculated, should be compared with the 8-hour TWA exposure for all ofthe dust collected in the sample, including both the organic and inorganic components ofthe dust.The second fair notice issue is related to st itis error to treat it as nuisance dust when considering a [crystalline quartz] silicaviolation.\”BWe have already concluded that the mineral dust standard applies only tomineral dusts. \u00a0Because it is undisputed that soybean dust is not a mineral dust, thecrystalline quartz silica provision of the mineral dust standard cannot be applied to thecited conditions. Accordingly, this alternative allegation in Docket No. 77-1622 must alsobe vacated.In reaching this conclusion, we are guided by the principle that two relatedprovisions of single standard must be interpreted in the context of the standard as awhole.\u00a0 See State Highway Commission of Missouri v. Volpe; 2ASutherland Statutory Construction ? 46.05.\u00a0 It would be inconsistent for us tohold that the inert or nuisance dust provision does not apply to soybean dust, while thecrystalline quartz silica provision of the same table does apply to soybean dust. \u00a0Bunge cites to the testimony of the Secretary’s witnesses that the PEL’s for inert ornuisance dust and for crystalline quartz silica, as they are interpreted by the Secretary,are in effect PEL’s for nuisance dust containing quartz.\u00a0 Therefore, since the PEL’sfor inert or nuisance dust do not apply to soybean dust, the formulas for reducing thosePEL’s when quartz is present in the dust also do not apply.We find considerable merit in Bunge’s analysis.\u00a0 However, we also observeanother fundamental inconsistency in attempting to apply the crystalline quartz silicaprovision to grain dust.\u00a0 We vacate the nuisance dust allegation on ground that theinert or nuisance dust PEL’s are set forth in a table that applies only to mineraldusts.\u00a0 The crystalline quartz silica PEL’s are included in the same table, TableZ-3.\u00a0 The mineral dust standard does not give fair notice that its inert or nuisancedust provision applies to a dust that is predominantly organic.\u00a0 We find the samenotice 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 noneof 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 thecrystalline quartz silica provision deprives grain handlers of their due process rights tofair notice of the standard’s requirements.\u00a0 We note that, in contrast to the inertor nuisance dust allegation, there is not even a claim by the Secretary of a commonunderstanding that the crystalline quartz silica PEL’s are applicable to grain dust.\u00a0Certainly, the Secretary cannot rely on any publicity surrounding his enforcementposition, for this appears to be the first and only effort to apply this provision to thistype of dust.[[22]]\u00a0 In fact, we are unaware of any other enforcement action wherethe Secretary sought to apply the crystalline quartz silica provision to a dust that wasnot wholly, or at least predominantly, silica dust.\u00a0 Nor is there any legislativehistory to support the Secretary’s interpretation of this provision.\u00a0 The 1968ACGIH-TLV’s pamphlet, which is the source document, provides no more guidance onthe meaning and application of the crystalline quartz silica provision than does the OSHAmineral dust standard itself.\u00a0 Neither the standard, the source document, nor anyother written materials that we are aware of explains the Secretary’s interpretation andapplication of the provision.\u00a0 Indeed, our only information on these matters is thetestimony of IH Gribble and Dr. Richard.We are left then with the language of the standard, which Bunge correctlycharacterizes as \”virtually indecipherable.\”\u00a0 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.\”\u00a0 The \”material\” that islisted is crystalline quartz silica and the table in which it is listed is captioned\”Mineral Dusts.\”\u00a0 To begin with, we could not reasonably expect that anemployer looking through the Secretary’s standards to find the PEL’s for grain dust wouldread 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 considerabledifficulty in determining whether it had exceeded the PEL’s.\u00a0 It would have to guessthe meaning of the notations \”% Si02\” and \”% S202 in the two formulas fordetermining the PEL’s.\u00a0 Is one of them a typographical error or do they refer to twodifferent substances?\u00a0 Do they refer to all silica in the sample or just the silicathat is crystalline quartz?\u00a0 The employer would then have to decide whether to statethe percentages as whole numbers (as the witnesses did) or as their decimal equivalents(as is more common in performing mathematical computations). \u00a0 Finally, once theemployer calculated the PEL’s, it would have to recognize that, contrary to the languageof 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 respirable dust, including boththe organic and inorganic components of the dust.\u00a0 In view of these manyuncertainties and ambiguities, we conclude that a reasonable employer in thegrain-handling industry would not understand from reading the crystalline quartz silicaprovision of the mineral dust standard that it is to be interpreted and applied in themanner described by the Secretary’s witnesses.\u00a0 The provision as applied to the factsof this case does not give fair notice of its requirements.[[23]]IIIThe separate citations in Docket Nos. 78-0838 and 78-2213 allege violationsof 29 C.F.R. ?? 1910.1000(c) and (e), based on the provision of section 1910.1000 thathas been referred to throughout this decision as \”the inert or nuisance dustprovision\” of the \”mineral dust standard.\”\u00a0 Neither case involves anyallegation under the crystalline quartz silica provision of the mineral duststandard.[[24]]\u00a0 No hearing has been held in either case.\u00a0 Instead, theSecretary and Bunge entered into stipulated settlement agreements.\u00a0 The twoagreements are essentially identical. \u00a0 The key provision of both agreements, as itis stated in the agreement filed in Docket No. 78-0838, provides:Whereas each of the parties herein have spent a substantial amount in thepreparation and trial of OSHRC Docket No. 77-1622 . . . ; and whereas the identical issueis presented herein; the parties therefore stipulate and agree to be bound by the highestdecision rendered in OSHRC Docket No. 77-1622, whether by the Occupational Safety andHealth Review Commission, the United States Court of Appeals, or the United States SupremeCourt, so that if grain dust ultimately is held to be a nuisance dust . . . within themeaning of . . . Table Z-3……, this matter shall be heard on the merits, and if graindust 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 decisionsin Docket Nos. 78-0838 and 78-2213.\u00a0 In both of these cases, he concluded that theissues were ripe for decision.\u00a0 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 inertor nuisance dust provision does not apply to employee exposure to grain dust.\u00a0 Onreview, the Secretary argues, and Bunge agrees, that the judge acted prematurely invacating in citation items at issue in Docket Nos. 78-0838 and 78-2213.\u00a0 The partiescontend that the judge erred in failing to wait for \”the highest decision rendered inOSHRC Docket No. 77-1622\” within the meaning of their settlement agreements.We disagree.\u00a0 Judge Oringer acted properly in taking action to remove thesetwo cases from this docket.\u00a0 In addition, the parties have not been prejudiced as aresult of the judge’s action.\u00a0 By deciding these three cases as a consolidated unit,we have accomplished the result the parties sought to achieve through their settlementagreement.\u00a0 The inert or nuisance dust provision has been uniformly applied in allthree 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 citationitems in Docket Nos. 78-0838 and 78-2213.\u00a0 For the reasons stated previously, weagree with the judge that the citation items must be vacated because inert or nuisancedust provision of the mineral dust standard does not apply to employee exposure to graindust.IVIn Docket No. 77-1622, the judge’s decision is affirmed with respect to theallegations under the inert or nuisance dust provision and reversed with respect to theallegations under the crystalline quartz silica provision.\u00a0 In Docket Nos. 78-0838and 78-2213, the judge’s decisions are affirmed.\u00a0 All citation items at issue onreview in this consolidated proceeding, including alternative allegations, are vacated.FOR THE COMMISSIONRay H. Darling, Jr.Executive Secretary Dated:\u00a0 April 22, 1986The Administrative Law Judge decision in this matter is unavailable in thisformat.\u00a0 To obtain a copy of this document, please request one from our PublicInformation 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. ?1910.1000 that, takentogether, require employers to implement protective measures whenever their employees areexposed to mineral dust levels that exceed any of the permissible exposure limits(\”PEL’s\”) listed in Table Z-3 of ?1910.1000.\u00a0 \”Inert or nuisancedust\” is one of the listed substances that is regulated under the mineral duststandard.\u00a0 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 thissection shall be limited in accordance with the requirements of the following paragraphsof this section.(c) Table Z-3:\u00a0 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 weightedaverage limit given for that material in the table.TABLE Z-3 — MINERAL DUSTS Substance \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Mg\/M3 Inert or Nuisance Dust: Respirable fraction …………5mg\/M3 Total dust …………………….15mg\/M3 (e) To achieve compliance with paragraph (a) through (d) of this section, administrativeor engineering controls must first be determined and implemented whenever feasible. \u00a0When such controls are not feasible to achieve full compliance, protective equipment orany other protective measures shall be used to keep the exposure of employees to aircontaminants within the limits prescribed in this section. . . . Whenever respirators areused, their use shall comply with ? 1910.134.[[2]] \”Crystalline quartz silica\” is another substance that is regulatedunder the \”mineral dust standard.\”\u00a0 In addition to containing the PEL’s for\”inert or nuisance dust,\” Table Z-3 of ? 1910.1000 also sets forth thefollowing PEL’s for \”crystalline quartz silica\”:TABLE Z-3 — MINERAL DUSTS Substance * Mg\/M3 Silica: Crystalline: 10 mg\/M3 Quartz (respirable) ……… * % SiO2 + 2 Quartz (total dust) ………. * 30 mg\/M3 % S2O2 [sic] + 2 [[3]] Bunge presents three challenges to the propriety of the Secretary’s enforcementprocedures in Docket No. 77-1622.\u00a0 First, it argues that, contrary to therequirements of ? 8(a)(2) of the Act, 29 U.S.C. ? 657(a)(2), the underlying inspectionwas not conducted \”within reasonable limits and in a reasonable manner.\” \u00a0More specifically, it contends that the inspection was unreasonable because the aircontaminant samples taken by the Secretary were obtained under conditions that were notrepresentative of the conditions that usually existed at its workplace.\u00a0 Bunge alsoargues that the judge erred in granting two motions by the Secretary to amend theallegations of violation contained in the citation.\u00a0 Finally, Bunge charges that,during the period between the filing of its notice of contest and the beginning of thehearing, the Secretary engaged in a series of misrepresentations and abuses of procedurethat in combination \”subverted the Act’s fundamental process.\”\u00a0 Accordingto Bunge, the Secretary 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.\”\u00a0 Respirable dust samples are also \”nonspecific\” inthe sense of capturing any kind of particulate material in the air.\u00a0 However, theyare designed to collect only respirable particles, which are 10 microns or less inlength.\u00a0 This size separation occurs when a device called a \”cyclone\” isused in conjunction with the sampling device.[[5]] The samples were taken in the breathing zones of three Bunge employees.\u00a0 A sampling device containing a filter was placed on Lionel McZeal while he workedon the shipping gallery.\u00a0 The filter collected 5.81 mg of total dust.\u00a0 Usingthis figure in conjunction with other relevant data, IH Gribble calculated McZeal’s 8-hourtime weighted average (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 thanthe 15 mg\/M3 PEL set forth in Table Z-3.\u00a0 A second sampling device with a cycloneattached so that only respirable dust would be collected was placed on Rickie Cure as heworked on the fourth floor bin deck.\u00a0 The filter collected 9.96 mg of respirabledust.\u00a0 Cure’s 8-hour TWA exposure was calculated to be 12.14 mg\/M3.\u00a0 Thus,Cure’s exposure exceeded the 5 mg\/M3 PEL for respirable inert or nuisance dust.\u00a0 Thethird sampling device was placed on Joseph Charles while he worked on the fourth floor bindeck.\u00a0 The filter collected 18.94 mg of dust (total dust).\u00a0 The 8-hour TWAexposure for Charles was calculated to be 26.05 mg\/M3.\u00a0 This exposure exceeded the 15mg\/M3 PEL for total inert or nuisance dust.[[6]] The Secretary charged a violation of the mineral dust standard on theshipping gallery based solely on the sampling of McZeal’s exposure, which did notestablish a violation of the inert of nuisance dust provision of the cited standard.\u00a0 See note 5 supra.\u00a0 There is no explanation in the record for thisanomaly.[[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.\u00a0 On November 15, lab chemist Dixon conducted a second petrographic analysis on oneof the samples.\u00a0 This analysis confirmed Germ’s report that crystalline quartz silicawas present in the sample.\u00a0 Dixon was unable to make a quantitative determination.\u00a0 At the hearing, Dixon testified that various treatments of the sample between June27 and November 15 had removed almost all of the material on the filter \”and justabout everything I saw at that point was quartz.\”\u00a0 Dixon hypothesized that thecrystalline quartz silica he saw on November 15 had been in the sample all along, but thathe had been unable to see it on June 27 because of the \”interference\” of anorganic \”coating.\”\u00a0 In his opinion, when this coating was removed,primarily through \”chemical ashing\” (treatment with phosphoric acid), he wasable to see the quartz and confirm its presence in the sample.[[8]] The \”A.C.G.I.H.\” is the American Conference of GovernmentalIndustrial Hygienists.\u00a0 As discussed more fully infra, its \”TLVCommittee\” drafted the standard that was the indirect source of the mineral duststandard.\u00a0 It appears from the source document that \”Herbert E. Stokinger,Ph.D.,\” was the chairman of the committee that drafted the standard.\u00a0 See Exh.J-1 (for judicial notice) at page 26.\u00a0 In addition, a second ACGIH publicationintroduced into the record as Exh. J-2 (for judicial notice) lists \”Herbert E.Stokinger, Ph.D.\” as a member of the \”1977 TLV Airborne ContaminantsCommittee.\”\u00a0 The record does not otherwise identify Stokinger or elaborate onthe telephone conversation with him.[[9]] On February 2, 1978, approximately three weeks before the hearing in DocketNo. 77-1622, OSHA issued Program Directive #300-11, which expressly cancelled the July 13Wilson-Tice memo.\u00a0 In this document, which was signed by the same Deputy DirectorWilson, OSHA interpreted the Table Z-3 PEL’s for inert or nuisance dust as applying to alltypes of nuisance dust, both organic and mineral, and as specifically including soybeandust.[[10]] 29 C.F.R. ? 1910.1499 identifies the source of ? 1910.1000 (including themineral dust standard) as 41 C.F.R. ? 50-204.50. This was a standard originally issuedunder the Walsh-Healey Act and later adopted as an \”established Federalstandard\” under ? 6(a), 29 U.S.C. ? 655(a), of the Occupational Safety and HealthAct.\u00a0 In turn, the Walsh-Healey standard was largely based on a non-governmentalconsensus standard developed by the ACGIH (American Conference of Governmental IndustrialHygienists).\u00a0 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 ACGIHpamphlet titled Threshold Limit Values of Air-borne Contaminants (sic) for 1968:\u00a0Recommended 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.\u00a0 As stated in the preface to the 1968ACGIH-TLV’s pamphlet, a TLV is an airborne concentration of a substance thatrepresents the level at \”which it is believed that nearly all workers may berepeatedly exposed, day after day, without adverse effect.\”\u00a0 The nature of thisadverse effect \”may differ from substance to substance; protection against impairmentof 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.\”\u00a0 The TLV is \”based on the available information from industrial experience,from experimental human and animal studies, and when possible, from a combination of thethree.\”Thus, \”TLV\” is an industrial hygienist’s term and, as the ACGIHexplained, the limits \”are intended for use in the field of industrial hygiene.\”\u00a0 In contrast, \”PEL\” is a legal term referring to a limit that may not beexceeded or a limit that triggers certain legal obligations when it is exceeded. \u00a0When the Secretary of Labor incorporated the TLV’s developed by the ACGIH into hisoccupational health standards, he thereby transformed the TLV’s into legally enforceablePEL’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.\u00a0 The list includes both organic and inorganicsubstances and both mineral and vegetable dusts.\u00a0 For example, four of the componentsof 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 includedon the list.\u00a0 The pamphlet also contains a section in the preface that explains theterms \”‘Inert’ or Nuisance Particulates.\”\u00a0 This section similarly refers toboth organic and inorganic substances as examples.\u00a0 The Secretary also introducedinto the record the 1977 version of the ACGIH pamphlet, which was the most recent versionat the time of hearing.\u00a0 That pamphlet similarly includes a list of particulates andan explanatory section that indicate an intent to include organic dusts within thecoverage of the TLV’s.[[12]] The same rules of interpretation are applicable in interpreting both statutes andadministrative regulations, such as the Secretary’s occupational safety and healthstandards.\u00a0 See, e.g., Ohio-Sealy Mattress Mfg. Co., 83 OSAHRC27\/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 inmineralogy, outlined the principal subcategories of silica.\u00a0 The two basic types arecrystalline silica, which is commonly called \”free silica,\” and amorphoussilica, which is not crystalline and therefore not classified scientifically as a mineral.\u00a0 Amorphous silica includes two subcategories–diatomaceous earth and dehydratedsilica gel.\u00a0 Free silica exists as quartz (i.e., crystalline quartz silica),tridymite, cristobalite, coesite and stishovite.\u00a0 1 PATTY’S INDUS. HYGIENE &TOXICOLOGY 185 (G.D. Clayton & F.E. Clayton 3d rev. ed. 1978)\u00a0 Each of theselast-mentioned substances is a \”polymorph\” of free silica, that is, each is amineral that has the chemical formula \”Si02\”.\u00a0 Quartz is the most common ofthese substances, not only in nature but also in occupational environments.[[14]] Lab chemist Dixon stated that three of the substances listed in Table Z-3are not classified scientifically as \”minerals\”: amorphous silica because it isnot crystalline, Portland cement (a silicate) because it does not occur in nature, andcoal dust because coal is organic.\u00a0 We assume that this testimony accuratelydescribes how a mineralogist would classify the substances.\u00a0 Nevertheless, it isclear 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.\” \u00a0Even the Secretary’s witnesses admitted this fact.\u00a0 For example, IH Gribble testifiedthat all of the Table Z-3 substances are mineral dusts with the exception of coaldust.\u00a0 Even coal, he conceded, is \”termed by many to be a mineral because it’smined from the ground.\”\u00a0 Dr. Richard gave similar testimony.\u00a0 With respectto coal dust, he stated that coal is considered to be a \”natural mineraldeposit\” despite its organic composition.[[15]] At the hearing, Dr. Thomas J. Culpepper, a witness for Bunge who was foundto be an expert in environmental analytical chemistry, testified that the term\”inert\” to a chemist means nonreactive.\u00a0 For this reason, he concluded thatorganic 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 ofindustrial hygienist Gribble and Dr. Richard, showing that, prior to the instant citationagainst Bunge, both federal and state officials had issued citations to several grainhandlers for dust levels exceeding the inert or nuisance dust PEL’s.\u00a0 The Secretaryalso proved that his enforcement actions had been publicized both in trade journals and ina magazine published by OSHA.\u00a0 In his brief to the Commission, the Secretary citesthis evidence as proving that the term \”nuisance dust\” is commonly understoodwithin the grain-handling industry as including grain dust.\u00a0 He cites no otherevidence in support of that proposition.[[17]] We further observe that, even if an employer were aware of the standard’sACGIH precursors, it would be very difficult for him to discover the intent of the ACGIHin developing its TLV’s for inert or nuisance dust.\u00a0 At the hearing, IH Gribbletestified that it had been difficult for him–a professional industrial hygienist and amember of the ACGIH–to obtain a copy of the 1968 pamphlet so that he could review theACGIH’s explanatory sections.\u00a0 Certainly today it would be even more difficult for anemployer engaged in grain handling to obtain a copy.\u00a0 Under these circumstances, itwould be unreasonable to expect employers to refer to source materials, and especiallythese ACGIH source materials, outside of the OSHA standard itself in order to give to thestandard’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 bedetermined by inserting the number 100 (representing 100% quartz) into the two formulasset forth in the mineral dust standard.\u00a0 See note 2 supra.[[19]] Even if we were to conclude that the mineral dust standard applied to graindust containing silica, we could not sustain the citation with respect to the allegationthat total dust levels exceeded the PEL’s for crystalline quartz silica, since thoseallegations rest solely 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.\u00a0 Thus,Gribble inserted the number 3.5 into the respirable dust formula to obtain a respirabledust PEL of 1.81 mg\/M3 for the fourth floor bin deck.\u00a0 He inserted the numbers 2.4and 4.6 into the total dust formula to obtain total dust PEL’s of 6.82 mg\/M3 and 4.54mg\/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 beenmade with respect to crystalline quartz silica on the shipping gallery.\u00a0 Gribblereferred to guidelines set forth in an OSHA Industrial Hygiene Manual, although he did notstate which edition of the manual or which section he was referring to.\u00a0 Under thoseguidelines, as described by the witness, once he had determined the applicable PEL, heshould then have adjusted it by multiplying the PEL by the \”statistical correctionfactor.\”\u00a0 This adjustment is made to take into account the possibility of errorin the collection of the sample and in the laboratory determination of the percentage ofcrystalline quartz silica.\u00a0 It accomplishes this goal by increasing the PEL to add ina margin of error.\u00a0 Gribble also testified that, for a total dust sample, thestatistical correction factor was 1.25.\u00a0 Thus, the adjusted PEL for total crystallinequartz silica on the shipping gallery was 8.5 mg\/M3 (1.25 x 6.82).\u00a0 Since LionelMcZeal’s 8-hour TWA exposure was only 8.06 mg\/M3, exposure to excessive dust levels wasnot established under the Secretary’s internal guidelines.[[22]] At the hearing, the Secretary’s counsel stated that, to the best of hisknowledge, this was the first time a granary had ever been charged with a violation ofthis provision.\u00a0 In addition, the two lab chemists who analyzed the Bunge samplesindicated that they were probably the first grain dust samples the Salt Lake City testinglaboratory had ever analyzed for silica content.\u00a0 While these chemists furthertestified that similar analyses were conducted after the analysis of the Bunge samples, weare unaware of any subsequent citation of a grain handler under the crystalline quartzsilica provision.[[23]] Indeed, we are not persuaded that the Secretary’s interpretation andapplication of the crystalline quartz silica provision is consistent with the intent ofthe ACGIH, which drafted the source TLV’s.\u00a0 Although IH Gribble and Dr. Richard gaveconsistent testimony to the effect that the PEL’s cover all silica-bearing dusts, neithercited any document stating that the PEL’s should be applied to predominantly organic dustssuch as grain dust.\u00a0 There is certainly nothing in the ACGIH source document thatsupports this conclusion.More importantly, however, we are unable to conclude that application of thecrystalline quartz silica provision to grain dust would have the effect intended by theACGIH.\u00a0 Based on the ACGIH’s explanation of how it develops its TLV’s, it appearslikely that the TLV’s for crystalline quartz silica were primarily designed to protectemployees from fibrotic changes to the lung, including specifically the risk ofcontracting silicosis.\u00a0 Yet, the documentary evidence presented by the Secretarysuggests that it is virtually impossible to contract silicosis through exposure to graindust.In particular, we note the epidemiological survey and research study admitted intoevidence as Secretary’s Exhibit B.\u00a0 Williams, Skoulas & Merriman, Exposure toGrain Dust:\u00a0 I.\u00a0 A Survey of the Effects, 6 J. OCCUP. MED. 319 (Aug. 1964)(hereafter Williams).\u00a0 Significantly, these researchers observed that, withthe exception of a single case reported in 1944, \”there has been no report in theliterature supporting the possibility that free silica in grain dust might be a factor inthe resultant respiratory disease.\” Williams at p. 320.\u00a0 Indeed, theseresearchers 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 ofthe dust.\u00a0 It is known that lifetime exposure to the dust of desert sands does notlead to the development of silicosis.\u00a0 Likewise, there is no evidence that the freesilica in soil dust can produce the disease.\u00a0 It is unlikely that the very smallamount of free silica in the organic fraction could produce silicosis. \u00a0 Moreover,the silica is closely bound physically to the organic material and there is none of thecrushing or grinding of silicious material which creates a silicosis hazard.\u00a0Therefore . . . there is strong evidence against silica playing any role in therespiratory disease associated with exposure to grain dust.\u00a0 Williams at p. 326.\u00a0 In the absence of any reason to believe that the quartz within grain dust createsany hazard whatsoever, we cannot conclude that the Secretary’s interpretation of thecrystalline quartz 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.\u00a0 Because these requirements are incorporated byreference 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 conditionsonly if the inert or nuisance dust provision can be applied to those conditions.”