“Docket No. 87-0692 SECRETARY OF LABOR.Complainant.v.PRIDE OIL WELL SERVICE,Respondent.OSHRC Docket No. 87-0692DECISION Before:FOULKE, Chairman: WISEMAN and MONTOYA,Commissioners. BY THE COMMISSION:As a result of an accident investigation and inspection bythe Occupational Safety and Health Administration (\”OSHA\”), Pride Oil WellService (\”Pride\”) was charged with serious violations of standards promulgatedunder the Occupational Safety and Health Act of 1970, 29 U.S.C. ?? 651-678 (\”theAct\”), because it failed to provide: (1) respiratory protection to employees involvedin monitoring the contents of a mobile storage tank from an opening in its top; or (2) asign warning of potential hazards or unsafe practices involving the tank.\u00a0 At issueis whether Review Commission Administrative Law Judge E. Carter Botkin erred in concludingthat Pride committed these alleged violations.I. BackgroundPride is an oil well service company with its principaloffice located in Houston, Texas. Pride and several other subcontractors had crews workingto restore a well in Angleton, Texas, to be operational again.\u00a0 Tommy Mostyn, adrilling consultant, had been hired by the owner of the well to oversee the entireproject. Mostyn, in turn, gave directions to George Cantu, Pride’s rig supervisor, or\”tool pusher,\” who was responsible for supervising Pride’s crew.As part of the process to \”recomplete\” the well,another subcontractor used tubing to insert liquid nitrogen, under pressure, into the wellto force diesel oil, water, and other materials from the well bore and into a 500-gallon\”frac tank,\” or mobile storage tank (\”the tank\”). During this process,liquid nitrogen changed into nitrogen vapor or gas, an odorless asphyxiant, that combineswith the vapors or gases from the diesel oil and other hydrocarbons present in the tank toform a gaseous mixture that is heavier than air. This mixture then displaces the oxygen inthe tank, forcing it out through the tank’s vent holes.In order to determine how deeply to drill, Mostyn neededto know the level of the \”returns,\” or the fluid that was coming out of the welland into the tank. He ordered Cantu to have an employee go up onto the top of the tank tomonitor the flow of the \”returns\” from an opening there, but Cantu protested.Cantu testified that he told Mostyn that it was unnecessary to have employees on top ofthe tank because he \”had already rigged up a way to get a sample off the needlevalve\” which was observable from the ground. When Mostyn persisted, Cantu relentedand assigned Mario Perez, a Pride floor hand, to go up on the tank to observe the level ofthe \”returns.\”The opening in the top of the tank through which the levelof the \”returns\” could be observed measured 18-1\/2 inches square, with ahatchway cover that had been left open for monitoring purposes. Nearby, there was a small,circular hole that measured three inches in diameter. There was a ladder on the exteriorof the Tank leading to its top, but no ladder leading down into the interior of the tank.Perez testified that he had to kneel and look down into the hatchway opening, sometimessticking his head through the opening, in order to perform his assignment to check theflow of the liquid. [[1]]To relieve Perez for lunch, Cantu assigned Rodrigo Reyes,another Pride floor hand, to go up on the tank. When Perez came down, Cantu was talkingwith another Pride employee, Arnoldo Zamora. Cantu testified that Perez asked him what wascoming out of the well because it was \”making [him] real dizzy\” and \”making[his] head hurt.\” Cantu responded that, as far as he knew, diesel, nitrogen, and somegas were coming out of the well. When Perez told Cantu that he was not going back up,Cantu said that was \”[f]ine\” and went for a coffee break. Cantu testified thatwhen he left for that break, he saw Reyes sitting within one to two feet of the hatchwayopening. [[2]]About five minutes after Cantu had gone on his break,Mostyn went into the trailer house and told Cantu that one of his men had fallen into thetank. Cantu climbed on top of the tank, after having learned that one of the older Prideemployees had already responded to the accident by closing the wing valve at the wellhead. When he called for Zamora, whom he had spoken to before taking the break, anotheremployee told Cantu that Zamora also had gone into the tank, apparently for a rescueattempt. When Cantu observed through the opening a body floating that still had handmovement, he took a deep breath and entered the tank. However, this rescue attempt wasunsuccessful. Cantu himself became dizzy and weak in his knees and then collapsed. Notuntil an air hose was thrown down to him was Cantu able to breathe sufficiently to climbout of the tank.The autopsy reports stated that both Reyes and Zamora haddied as a result of: \”Asphyxia due to drowning (diesel and H2O).\” Also noted inReyes’ autopsy report was the presence of \”[m]ultiple abrasions and contusions\”on the upper front of the head. The judge found that these \”abrasions andcontusions\” were consistent with Reyes having lost consciousness and then fallinginto the tank. The opinion of the forensic pathologist, who performed the autopsies, wasthat each employee died \”as a result of asphyxia due to drowning, accidental, whileat work.\”It is undisputed that Pride did not provide anyrespiratory protection to these employees, nor was there any sign posted to cautionemployees regarding potential hazards or unsafe practices involving the contents of thetank. When asked if the employees had been \”trained in any way about oxygen-deficientatmospheres,\” Pride’s supervisor Cantu testified that he personally had not been. Hefurther testified that there was no equipment at the worksite for testing the oxygen levelin the tank. Moreover, the OSHA compliance officer who conducted the investigation and theinspection testified that she concluded that Pride employees had not been given anytraining in oxygen deficiency, and that \”[s]ome of them didn’t even know what itwas.\”Following the OSHA investigation and inspection, Pride wasissued a citation alleging, as amended in the complaint, serious violations of therespiratory protection standard at 29 C.F.R. ? 1910.134(a)(2) and the caution signstandard at 29 C.F.R. ? 1910.145(c)(2)(i). [[3]] On April 2, 1990, this case was directedfor review on issues relating to the judge’s affirmance of these two citation items.II. Respiratory ProtectionCitation no. 1, item 2, as amended, alleges that Pridecommitted a serious violation of 29 C.F.R. ? 1910.134(a)(2) [[4]] by failing to providerespiratory protection to employees involved in monitoring the \”returns,\” aswell as those employees who had attempted rescue. In order to establish a violation of aspecific standard, the Secretary must prove by a preponderance of the evidence that: thestandard applies to the cited condition; the employer failed to meet the terms of thestandard; its employees had access to the violative condition; and the employer eitherknew or could have known of the condition with the exercise of reasonable diligence. E.g.,Astra Pharmaceutical Prods., 9 BNA OSHC 2126, 2129, 1981 CCH OSHD 25,578,pp.31,899-900(No. 78-6247, 1981), aff’d in pertinent part, 681 F.2d 69 (1st Cir.1982).Pride does not dispute that it failed to providerespirators to its employees, and that its employees had access to the cited condition.However, Pride contends that (1) to prove that respiratory protection was \”necessaryto protect the health of the employee,\” as the cited standard requires, the Secretarymust show that the cited condition involved \”contaminated\” air causing\”occupational diseases,\” as the preceding subsection of the respiratoryprotection standard requires; (2) the standard is unenforceably vague in light of industrypractice; (3) it had no knowledge of the violative condition; and (4) the violation wasthe result of unpreventable employee misconduct.A. Whether the secretary Proved the Requisite HealthHazard 1.What Health Hazard Must Be EstablishedSection 1910.134(a)(2) requires the provision ofrespirators \”when such equipment is necessary to protect the health of theemployee.\” Pride argues that, in order to prove a violation of section1910.134(a)(2), the Secretary must show, as the preceding subsection at 29 C.F.R. ?1910.134(a)(1) [[5 ]] requires, that the cited condition involved \”occupationaldiseases\” caused by breathing \”contaminated\” air. According to Pride, shehas not met that burden in this case. Pride argues that, because subsection (a)(1) ends byreferring to \”the following requirements,\” it is necessary to read it togetherwith subsection (a)(2) to learn what those requirements are. Pride contends that theSecretary failed to prove that Pride’s employees were exposed to an \”occupationaldisease\” caused by \”air contaminated with harmful,dusts, fogs, fumes, mists,gases, smokes, sprays, or vapors.\”The judge correctly ruled below that the requirements ofsubsection (a)(2) are to be read independently of subsection (a)(1).In Brock v City OilWell Service Co. (\”City\”), 795 F.2d 507 (5th Cir. 1986), the employer had beencited for violating both sections 1910.134(a)(1) and (2) for failing to providerespirators to protect the health of employees on top of a \”frac tank\” againstexposure to hydrogen sulfide gas (\”H2S\”), \”a deadly byproduct of oil andgas production.\” 795 F.2d at 508 & n.1. The Fifth Circuit, to which this case canbe appealed, [[6]] rejected City’s argument that subsection (a)(1) required the Secretaryto prove that engineering controls were not feasible before a requirement for respiratoryprotection arose under subsection (a)(2). More specifically, the court also rejected theargument that the language in subsection (a)(1) concerning the feasibility of engineeringcontrols must be read into (a)(2), declaring that \”the requirements of (a)(2) … areindependent of and can form the basis of a violation distinct from (a)(1).\” 795 F.2dat 510 n. 5. Cf.Snyder Well Servicing, Inc., 10 BNA OSHC 1371, 1375-76, 1982 CCH OSHD ?25,943, pp. 32,510-11 (No. 77-1334, 1982) (implicit rejection of employer’s argument basedon similar facts).Therefore,based on the decisions noted above, we rejectPride’s argument that, before she can establish a violation of subsection (a)(2), theSecretary must show that Pride’s employees were exposed to an \”occupationaldisease\” caused by \”contaminated\” air, as discussed in subsection (a)(1).2. Whether the Secretary Has proven that Respirators Were\”Necessary to protect the Health of the Employee\”The next issue for consideration is whether the judgeerred in finding that the Secretary established that respirators were \”necessary toprotect the health of the employee.\” In addressing the question of the need forrespirators, the judge particularly relied on the testimony of the Secretary’s RegionalIndustrial Hygienist Richard Wingo. Wingo testified that nitrogen displaces oxygen in aconfined space and that when the oxygen falls below 19.5% of the air’s content, theresults can be: impairment of vision and mental capabilities; dizziness and fainting;unconsciousness; and even death. The judge found Wingo to he a \”well-qualifiedindividual\” and an \”impressive and highly credible witness.\” The judgestated that, when he viewed Wingo’s testimony as a whole, \”it is obvious that heconsidered the nitrogen, diesel and other elements to be a contaminant of the air in thisconfined space, causing an oxygen deficient atmosphere. Without question, I hold thatview.\” (emphasis added; transcript reference deleted). The judge’s finding that theatmosphere in the tank was oxygen-defficient is supported by his determination, which isnot challenged by Pride, that \”the credible evidence establishes that he [Reyes] felland did not voluntarily enter the tank\”. The judge concluded that the employeesassigned to monitor the returns from atop the tank, as well as those attempting to rescue,were exposed to \”a hazard to the health (asphyxiation or drowning).\”Pride has not introduced any evidence to dispute Wingo’stestimony concerning the likelihood that the tank had an oxygen-deficient atmosphere onthe day in question.[[7]] Based on that testimony by Wingo and the weight of the evidenceestablishing that Reyes did not voluntarily go into the tank, we conclude that Pride’semployees were exposed to the hazard of asphyxiation, which resulted in their drowning. Wetherefore conclude that the judge did not err in finding that, in this case, respiratorswere \”necessary to protect the health of the employee.\”B.Whether the standard is Unenforceably VaguePride argues, as it did below, that section 1910.134(a)(2)is unenforceably vague because the standard’s requirement for respiratory protectiveequipment is so broadly worded that it fails to provide notice sufficiently specific tosatisfy due process concerns.When faced with such claims in relation to broadly-wordedstandards, the courts and the Commission have considered whether a reasonably prudentemployer, familiar with the circumstances,would recognize a hazard warranting the sameprotection in the cited standard. See Bratton Corp., 14 BNA OSHC 1893, 1898-98,1990 CCHOSHD 29,152, p. 38,993 (No. 83-132, 1990) and cases cited therein. As Pride notes, for thegenerally- worded, personal protection standards at 29 C.F.R. ?? 1910.132(a) and1926.28(a), the Fifth Circuit has determined that \”industry custom and practice willgenerally establish the conduct of the reasonably prudent employer ……\” Cotter& Co. v. OSHRC, 598 F.2d 911, 913 (5th Cir. 1979). Accord S & H Riggers &Erectors, Inc. v OSHRC, 659 F.2d 1273, 1285 (5th Cir. 198 1); Power Plant Div., Brown& Root, Inc. v. OSHRC, 590 F.2d 1363, 1365 (5th Cir. 1979); B & B Insulation, Inc.v. OSHRC, 583 F.2d 1364, 1370-71 (5th Cir. 1978).Pride notes that its supervisor Cantu and safetycoordinator Jimmy Harville both testified that the common practice in the well-servicingindustry is not to provide respirators, but rather to depend on the well operator or offerto provide respirators, as well as information about any dangerous condition concerningthe well. This is because the well owners and operators have records on the well that arenot available to well- servicing companies. Pride contends that, as it was not industrycustom to provide respirators, section 1910.134(a)(2) is unenforceably vague.In his decision, the judge rejected Pride’s argument,relying on the Fifth Circuit’s decision in City, supra, where the court squarely rejectedCity’s argument that the industry practice test that the Fifth Circuit itself had appliedwith regard to other standards (such as sections 1910.132(a) and 1926.28(a)) isappropriate for section 1910.134(a). The court stated that the employer’s reliance on thesame line of cases that Pride cites was \”misplaced\” because:The regulation here [section 1910.134(a)] is precise. InCity’s case, it concerns only one hazard and two remedies. The hazard is hydrogen sulfide. . . ; the two remedies are effective engineering controls and respirators, therequirements for the selection, use, and maintenance of which are set out in detail. SeegeneraIly 29 C.F.R. ? 1910.134.795 F.2d at 511.The court noted that City’s emphasis on the well-servicingindustry’s reliance on the well operator or owner to provide respirators was not onlyinappropriate under the cited standard, but also an improper attempt to \”use industrycustom to shift its statutory responsibility for the health and safety of its employees tothird parties.\” Id.Based on the Fifth Circuit’s decision in City, we findthat the judge did not err in his ruling on this issue. Furthermore, we note that theCommission has issued a decision that relies on City and holds that section 1910.134(a)(2)is not vague, and therefore the reasonable employer test is not needed to interpret andapply the standard. Power Fuels, Inc., 14 BNA OSHC 2209, 2213, 1991 CCH OSHD ? 29,304, p.39,346 (No. 85-166, 1991).We reject Pride’s argument that the Fifth Circuit andCommission decisions are factually distinguishable from this case because those decisionsinvolve the \”well-known\” hazard of H2S, instead of nitrogen. Section1910.134(a)(2) does not make any reference to how well-known any specific substance orcondition must be in order to require respirators. It states only that respirators must beprovided where they are \”necessary to protect the health of the employee.\”Nevertheless, we note that, as shown by Table 1 in the American National Standard, ANSIZ88.2-1969, Practices for Respiratory Protection, section 4 (1969),[[8]] oxygen deficiencyin tanks or other confined spaces resulting from nitrogen or another simple asphyxiantdiluting the oxygen in the air is a well-recognized respiratory hazard.Therefore, based on our own precedent and the decision inCity by the Fifth Circuit, to which this case can be appealed, we reject Pride’s argumentshere and find, as the judge did, that section 1910.134(a)(2) is not unenforceably vague.C. Whether Pride Had Knowledge of the Violative Condition 1. Whether the Secretary Proved KnowledgeAs noted above, to prove a violation the Secretary mustshow that the cited employer had knowledge of the violative condition. She can satisfythis burden by establishing that the employer either knew, or, with the exercise ofreasonable diligence, could have known of the presence of the violative condition. E.g.,Tampa Shipyards, Inc., 15 BNA OSHC 1533, 1537, 1992 CCH OSHD ? 29,617, p. 40,100 (No.86-360. 1992); Gary Concrete Prods., Inc., 15 BNA OSHC 1051, 1052, 1991 CCH OSHD ?29,344, p. 39,449 (No. 86-1087, 1991). The actual or constructive knowledge of theemployer’s foreman or supervisor can be imputed to the employer. Id.The judge concluded that the Secretary made a pirma facieshowing Pride’s supervisor Cantu actually knew, or could have known, with the exercise ofreasonable diligence, of the cited condition. He further found that Cantu’s actual orconstructive knowledge that respiratory equipment was necessary to protect the health ofthe employee was imputable to Pride.We find no error in the judge’s ruling that a prima facieshowing of Pride’s knowledge has been established based on the record. As the judge noted,Cantu’s actual knowledge of the conditions at the worksite that led to the violationscited here was established by Cantu’s testimony that Perez complained to him that what wascoming out of the tank was making [him] real dizzy\” and \”making [his] headhurt,\” and that he would not go back up on the tank. Cantu was given further noticeof the hazard when he learned that Reyes and Zamora were in peril. Nevertheless, Cantuattempted to rescue them before almost being overcome himself.The Secretary also proved that Pride had constructiveknowledge because its supervisor Cantu could have discovered and eliminated the hazardwith the exercise of reasonable diligence. Reasonable diligence involves several factors,including an employer’s \”obligation to inspect the work area, to anticipate hazardsto which employees may be exposed, and to take measures to prevent the occurrence.\”Frank Swidzinski Co., 9 BNA OSHC 1230, 1233, 1981 CCH OSHD 25,129, p. 31,032 (No. 76-4627,1981). Although Cantu personally objected to Mostyn’s instructions to put an employee onthe tank, in light of the on-ground sampling method that Cantu had put in place, Cantu didnot raise the matter at that time with his supervisors at Pride. However, he testifiedthat he had previously raised with them other orders from Mostyn. Moreover, Cantu admittedthat, even though he could not have done anything that Mostyn had not approved, the safetyof Pride’s crew was his own responsibility.As a crew supervisor, Cantu had a general responsibilityto acquaint himself with the contents of the tank and the hazards that they might pose toPride employees. This obligation was heightened when Perez complained to him that what wascoming out of the well was \”making [him] real dizzy\” and \”making [his] headhurt.\” In light of Perez’s complaint and the considerable likelihood of seriousinjury, Cantu could have at least told Mostyn or his supervisor at Pride about Perez’scomplaint and made inquiries. See Getty Oil Co. v. OSHRC, 530 F.2d 1143, 1146 (5th Cir.1976) (reasonable diligence includes \”simple expediency of … making inquiry\”).Evidence in the record indicates that Cantu knew thatnitrogen was being used to force the material out of the well, and that nitrogen anddiesel were present in the tank. He said as much to Perez in response to Perez’s questionfollowing his complaint of dizziness and a headache. Furthermore, Cantu had someunderstanding that the operations on the day of the accident were not typical. Hetestified that, based on his fifteen years of experience in the oil well business, thecontents of the well were not ordinarily put into an enclosed \”frac tank\” whennitrogen was being used. Cantu stated that when the operation involves jetting nitrogen,the returns from the well are usually directed into an \”open earth pit\” or an\”open 200 barrel, tank.\” Arguably, a reasonably diligent employer who was awareof this departure from normal procedures would have questioned Mostyn or the well operatorafter Perez complained, if not before.Other factors indicative of reasonable diligence includeadequate supervision of employees, and the formulation and implementation of adequatetraining programs and work rules to ensure that work is safe. Gary Concrete, 15 BNA OSHCat 1054-55, 1991 CCH OSHD at p. 39,451-52; see Towne Constr Co., 12 BNA OSHC 2185, 2190-91, 1986-87 CCH OSHD ? 27,760. pp. 36,312-13 (No. 83-1262, 1986), aff’d, 847 F.2d 1187(6th Cir. 1988). Although the record here shows instances where Cantu’s supervision of hiscrew was arguably not adequate, the real problem was that Pride had failed to formulateand implement adequate work rules and training programs to ensure that Cantu had beeninformed of the appropriate safety considerations. Cantu testified that he had not beentrained in what do in oxygen-deficient atmospheres, and, based on the evidence concerningthe accident day, apparently neither had any of his crew. However, he and his crew hadbeen made aware of the dangers of H2S and trained in how to respond to it, including howto use masks and oxygen tanks. Cantu’s lack of understanding of the oxygen deficiency inthe tank was most dramatically demonstrated when he went in the tank himself in the rescueattempt.Based on the considerations above, we conclude, as thejudge did, that the Secretary has made her prima facie showing that Pride had knowledge ofthe violative condition.2.\u00a0 Whether Pride Rebutted the Showing of KnowledgeTo rebut prima facie proof that the knowledge of asupervisor should be imputed to it, the cited employer must offer evidence that it had:established work rules designed to prevent the violation; adequately communicated thosework rules to its employees (including supervisors); taken reasonable steps to discoverviolations of those work rules; and effectively enforced those work rules when they wereviolated. E.g., Tampa Shipyards, Inc., 15 BNA OSHC at 1538,1992 CCH OSHD at p. 40,100;A.P. O’Horo Co., 14 BNA OSHC 2004, 2007-08, 1991 CCH OSHD ? 29,223, p. 39,129 (No.85-369, 1991).There is no evidence that Pride had a work rulespecifically addressing the hazards of oxygen-deficient atmospheres. Rather, Pride relieson its work rule for confined space entry under the theory that an employee sticking hishead through the opening in the top of the tank to observe the level of the\”returns\” would be violating that rule, as would an employee who entered thetank for rescue purposes. Pride contends that whatever knowledge Cantu might have had ofthe violative condition cannot be imputed to it because it had implemented, communicated,and enforced the following \”basic safety rule\” set forth in its \”EmployeeBenefit Summary and Safety Guide:\”Confined Spaces — Employees are not authorized to enterany confined spaces for any reason. Confined spaces are defined as frac tanks, storagetanks, tank hatches or any other spaces not fully ventilated to fresh air.We note that supervisor Cantu’s voluntary entry into thetank in his attempt to rescue his crew members was in clear violation of this work rule.Where a supervisor engages in misconduct and is exposed to the hazardous condition, thatis strong evidence of lax enforcement of the employer’s safety program. E.g., Brock v.L.E. Myers Co., 818 F.2d 1270, 1277 (6th Cir. 1987), cert. denied, 484 U.S. 989 (1987);Baytown Constr. Co., 15 BNA OSHC 1705, 1710, 1992 CCH OSHD ? 29,741, p. 40,414 (No.88-2912-S, 1992).Pride could have prevented this conduct by sufficientlytraining Cantu in the hazards of, and procedures necessary for, oxygen-deficientatmospheres. However, Cantu testified that Pride failed to provide this type of training,and Pride presented no evidence that it had given such training. See Daniel Constr Co., 10BNA OSHC 1549,1552, 1982 CCH OSHD ? 26,027, p. 32,672 (No. 16265, 1982). As Cantu’stestimony indicated, nitrogen is not uncommonly used in the well-servicing industry, andits diluting effect on oxygen should have been made known to all employees, especiallysupervisors.The Act places final responsibility for compliance withits requirements on the employer. E.g., City, 795 F.2d at 511, quoting section 5(a)(2) ofthe Act, 29 U.S.C. ? 654(a)(2) (\”[e]ach employer …shall comply\” with OSHAstandards) (court’s emphasis). An employer who has failed to address a hazard byimplementing and enforcing an effective work rule cannot shift to its employees theresponsibility for assuring safe working procedures. See, e.g., Stuttgart Machine Works,Inc., 9 BNA OSHC 1366, 1369, 1981 CCH OSHD ? 25,216, p. 31,142 (No. 77-3021, 1981). Anemployer \”cannot fail to properly train and supervise its employees and then hidebehind its lack of knowledge of their dangerous working practices.\” Danco Constr. Co.v. OSHRC, 586 F.2d 1243, 1247 (8th Cir. 1978). Here, Pride failed to adequately train itssupervisor in the respiratory hazard of, and the safety procedures for, oxygen deficiency,to which he and some of his crew were exposed. We therefore conclude that Pride has failedto rebut the Secretary’s showing, and we impute Cantu’s knowledge to Pride.D. Whether the Conduct of Pride’s Employees WasUnpreventable Pride further asserts that it was not in violation of thestandard because it did all that it could reasonably have done to prevent the violation.To prove the affirmative defense of unpreventable employee misconduct, the employer mustshow that it had established a work rule designed to prevent the violation, adequatelycommunicated those work rules to its employees (including supervisors); taken reasonablesteps to discover violations of those work rules; and effectively enforced those workrules when they were violated. See, e.g., Marson Corp., 10 BNA OSHC 1660, 1662, 1982 CCHOSHD ? 26,075, p. 32,804 (No. 78-3491, 1982).In the preceding section, we discussed whether Prideestablished that the conduct of its supervisory employee Cantu was unpreventable, which isnecessary to rebut the Secretary’s showing of knowledge imputed to from Cantu. Weconcluded that Pride did not prove that Cantu’s conduct was unpreventable and thereforedid not rebut the Secretary’s proof of knowledge.With regard to whether the conduct of its non-supervisoryemployees Reyes and Zamora was unpreventable, Pride introduced into evidence the pagesthat these two employees had signed acknowledging receipt of the safety guide in August1986, and \”agree[ing] to read all safety instructions pertinent to [their]jobs.\” With regard to Reyes, the work rule upon which Pride relies did not addressthe hazardous condition to which he was exposed when he was working atop the tank. As thejudge found, based on the autopsy report and testimony, the multiple abrasions andcontusions on the upper front of Reyes’ head showed that he had not entered the tankvoluntarily. The judge noted that under the work rule, employees \”could very wellconclude\” that they did not violate the work rule by merely sticking their heads inthe hole at the top of the tank to see the level of the returns inside the tank. Moreover,when specifically directed by a supervisor, as Reyes was by Cantu here, to perform workthat could possibly cause the employee to break a safety rule, the employee couldreasonably consider the supervisor’s instructions as overriding the safety rule. Cf.Regina Constr. Co., 15 BNA OSHC 1044, 1048, 1991 CCH OSHD 29,354, p. 39,468 (No. 87-1309,1991) (employee could not be in a hazardous location but for supervisor’s orders).With regard to Zamora, Cantu’s testimony as to whatanother employee told him demonstrates that Zamora attempted to rescue Reyes and thereforecould also have entered the tank voluntarily. If this had been the case, Zamora also wouldhave been in violation of the work rule. Nevertheless, the evidence also shows that Cantu,Zamora’s supervisor, was not only failing to enforce the rule, but he was breaking ithimself. Furthermore, it is arguable that the work rule does not really address thecondition that Cantu and Zamora faced–the necessity for an emergency rescue. As theSecretary notes, rescue attempts are readily foreseeable in the oil well servicingindustry, yet Pride had no work rule addressing them.[[9]]Just as Pride failed to adequately train its supervisorCantu and now seeks to hide behind his lack of knowledge of the hazard, so does it alsoattempt to hide behind Reyes and Zamora’s lack of training and supervision. As discussedabove, this is not permission. See Danco, 586 F.2d at 1247. Therefore, we reject Pride’scontentions that the conduct of Reyes and Zamora was unpreventable.E. Summary and PenaltyBased on our findings above, we conclude that the judgedid not err in determining that Pride committed a violation of section 1910.134(a)(2). Thejudge found that the violation was serious under section 17(k) of the Act, 29 U.S.C. ?666(k), as alleged. Pride does not challenge that characterization on review. We thereforeconclude that the violation was serious.The judge assessed the proposed penalty of $560 for thisviolation. In light of the penalty factors in section 17(j) of the Act, 29 U.S.C. ?666(j), especially the gravity of the violation, and the immediate, direct relief from thehazardous atmosphere that respirators could have provided, we assess a penalty of $1,000.Ill. Caution SignThe judge affirmed citation no. 1, item 3, as amended,which alleges a serious violation of 29 C.F.R. ? 1910.145(c)(2)(i). [[10]] It wasundisputed that there was no caution sign warning employees against the potential hazardsinvolved in monitoring the returns from the opening in the top of the tank or entering thetank for emergency rescue. The compliance officer testified that such signs could havecaused employees to exercise the necessary caution in light of the potential hazard.Pride’s supervisor Cantu testified that over the years he had seen \”frac tanks\”with signs on them saying things like: .\”poisonous gas, do not enter.\”Pride contends that, because it did not own the tank, butrather only leased it, it was not responsible for providing a caution sign. As notedabove, the Fifth Circuit stated in City that an employer \”cannot shift its statutoryresponsibility for the health and safety of its employees to third parties.\” 795 F.2dat 511. Moreover, from a practical standpoint, there is no requirement that the sign bepermanent. Nor does the sign need to be attached to the tank itself, but rather can be, asCantu testified he had seen, \”‘anywhere around it\” that would be visible toemployees.Pride also contends that it had taken sufficient measuresto warn employees by its safety manual. However, as discussed above, the work rule againstentering confined spaces, even assuming it implements the requirements of the citedstandard, was not enforced. Pride also argues that it did not know the contents of theatmosphere within the tank and therefore would have had no way of knowing whether warningsigns were needed. We reject that contention. As the discussions in the sections aboveshow, Pride did not take sufficient measures to either warn or train its employees, and itis now trying to hide behind the resultant lack of knowledge on its employees’ partregarding the possibility of oxygen deficiency.Based on the considerations above, including thewell-documented hazards in the record, [[11]] and Pride’s knowledge of them, we concludethat the judge did not err in finding that Pride violated section 1910.145(c)(2)(i). Pridedoes not challenge on review the serious characterization of this violation. Accordingly,we affirm the violation as serious.The judge assessed the proposed penalty of $560. Based onthe penalty factors in section 17(j) of the Act, 29 U.S.C. ? 666(j), we assess a moreappropriate penalty of $200. IV. OrderFor the reasons stated above. we affirm the decision ofJudge Botkin and find no error in his conclusions that Pride committed serious violationsof sections 1910.134(a)(2) and 1910. 145(c)(2)(l). We assess respective penalties of $1,000 and $200 for these violations.Edwin G. Foulke, Jr. ChairmanDonald G. Wiseman CommissionerVelma Montoya CommissionerDated: August 17, 1992FOOTNOTES: [[1]] The judge characterized this testimony by Perez as\”direct and persuasive.\” (Throughout his decision, he referred to this employeeas \”Mario\” because he mistakenly stated that, instead of Perez (as the employeespelled his own name at the hearing), his last name was Reyes, the last name of anotherPride employee.) The judge specifically credited Perez’s testimony over Cantu’s testimonythat he saw Perez walk over and lean down near the opening, as if to listen. We defer tothe judge’s credibility determination. See, eg., C. Kaufman, Inc., 6 BNA OSHC 1295,1297,1977- 78 CCH OSHD 22,481, p.27,099 (No.14249,1978).[[2]] Cantu testified that he told his crew to \”standup\” while monitoring the returns. The judge specifically discredited that statementdue to its inconsistency with Cantu’s earlier testimony that he did not know whatinstructions Reyes had received,even though Cantu was the one who had given him the orderto relieve Perez. Based on our review of the record, we see no need to disturb the judge’sevaluation of these parts of Cantu’s testimony. Moreover, even if Cantu had giveninstructions to stand up, he was put on notice that they were not being followed when, ashe testified, he observed Reyes sitting near the opening.[[3]] The Secretary also alleged a serious violation of 29C.F.R. 1910.23(a)(6). which requires that a \”manhole floor opening\” shall beconstantly attended when the cover is not in place.The judge vacated this item. TheSecretary does not challenge that ruling on review, and we do not consider it here. [[4]] The standard Provides:? 1910-134 Respiratory protection. (a)Permissable practice.. . . .(2) Respirators shall he provided by the employer whensuch equipment is necessary to protect the health of the employee. The employer shallprovide the respirators which are applicable and suitable for the purpose intended. Theemployer shall be responsible for the \”establishment and maintenance of a respiratoryprotective program which shall include the requirement outlined in paragraph (b) of thissection.[[5]] Section1910.134(a)(1)providesIn the control of those occupational diseases caused bybreathing air contaminated with harmful dusts, fogs, fumes, mists, gases, smokes, sprays,or vapors, the primary objective shall be to prevent atmospheric contamination. This shallbe accomplished as far as feasible by accepted engineering control measures …. Wheneffective engineering controls are not feasible,or while they are beinginstituted,appropriate respirators shall be used pursuant to the following requirements.(Emphases added.)[[6]] This case can be appealed to the Fifth Circuit basedon the locations of the alleged violation and the principal office of the employer. Seesections 11(a) and (b) of the Act, 29 U.S.C. ? 660(a) and (b).[[7]] Pride has not acknowledged that the atmosphere inthe tank was oxygen- deficient. It suggests that the Secretary must show the percentageoxygen in the atmosphere, which Pride notes she has failed to do. However,as the judgestated in his decision, it was not necessary for the Secretary to establish the percentageof oxygen in order to prove the hazard of oxygen deficiency existed. He additionally notedthat, despite Pride’s successful objection to the Secretary’s introduction of atmospherictesting results into the record. Pride itself introduced a statement as to the resultsinto evidence in one of its own exhibits. We further note that the conditions at the wellon the day before the accident, when nitrogen was not being inserted into the tank, arenot relevant to the citation items before us.[[8]] This ANSI standard was the source of OSHA’srespiratory protection standard at section 1910.134. See 29 C.F.R. ? 1910.139.[[9]] Pride does not have any general safety rules onrescues from tanks or wells. Included in its work rules concerning H2S is only theadmonition: Rescuers must exercise due caution.\”[[10]] \”The standard provides:? 1910.145 Specifications for accident prevention signs and tags.(a) Scope. (1) These specifications apply to the …use of signs…intended toindicate…specific hazards of a nature such that failure to designate them may lead toaccidental injury to workers….(c) Classification of signs according to use–. . . .(2) Caution signs. (i) Caution signs shall be used only towarn against potential hazards or to caution against unsafe practices.(Emphases added.)[[11]] In light of the oxygen-deficient atmosphere in thetank, which we found above, a \”danger sign\” (as discussed in 29 C.F.R {sym}1910.145(c)(l)) may have been appropriate to warn of the specific danger of asphyxiationto which employees were exposed while observing the level of the returns through theopening in the tank’s top.”