Opinion ID: 390180
Heading Depth: 2
Heading Rank: 1

Heading: Maximum Safe Individual Blood Lead Level

Text: 66 LIA attacks the Administrator's determination that 30 ug Pb/dl should be considered the maximum safe individual blood lead level for children, maintaining that there is no evidence in the record indicating that children suffer any health effects that can be considered adverse at this blood lead level. As previously noted, 52 the Administrator's selection was based on his finding that EP elevation at 30 ug Pb/dl is the first adverse health effect of lead exposure, and his determination that a maximum safe individual blood lead level of 30 ug Pb/dl will allow an adequate margin of safety in protecting children against the more serious effects of lead exposure anemia, symptoms of which appear at blood lead levels of 40 ug Pb/dl and central nervous system deficits which begin to occur at blood lead levels of 50 ug Pb/dl. 67 LIA challenges each of these findings. First, it contends that nothing in the record supports the suggestion that EP elevation at 30 ug Pb/dl is harmful to health, arguing that EP elevation is a mere subclinical effect a biological response to lead exposure which is without health significance, and noting that a number of its experts brought this matter to EPA's attention in their comments on the proposed standards. 53 In LIA's view, the Administrator did not explain precisely how impairment of heme synthesis at blood lead levels of 30 ug Pb/dl adversely affects the health of children. 54 Second, LIA challenges the Administrator's determination that a maximum safe individual blood lead level of 30 ug Pb/dl is justified by the need to allow an adequate margin of safety in protecting children against anemia and central nervous system deficits. It maintains that the evidence in the record does not support the Administrator's conclusion that the blood lead threshold for the symptoms of anemia in children is 40 ug Pb/dl. LIA claims that this error was brought to the Administrator's attention by comments on the proposed standard, but that he failed to respond to these comments, thereby violating the statutory provision requiring him to respond to significant comments, criticisms, and new data submitted    during the comment period. 55 Third, LIA contends that the preamble to the final regulations does not state the basis for the Administrator's finding that central nervous system deficits occur in children at blood lead levels of 50 ug Pb/dl, thereby precluding this court from being able to test the soundness of this determination. Finally, LIA argues that even if it were to concede that EPA's conclusions about the blood lead thresholds for anemia and central nervous system deficits are correct, there is still no explanation of why the Administrator concluded that a maximum individual safe blood level of 30 ug Pb/dl rather than 35 ug Pb/dl, for example is necessary to provide an adequate margin of safety against these effects. 68 Our review of the record persuades us that there is adequate support for each of the Administrator's conclusions about the health effects of lead exposure and, consequently, that LIA's challenges to the evidentiary support for these findings must be rejected. Under the statutory scheme enacted by Congress, the Criteria Document prepared with respect to each pollutant is to provide the scientific basis for promulgation of air quality standards for the pollutant. We have already noted that the Lead Criteria Document was the product of a process that allowed the rigorous scientific and public review that are essential to the preparation of a document accurately reflect(ing) the latest scientific knowledge useful in indicating the kind and extent of all identifiable effects (of lead exposure) on (the) public health   . 56 In our view, the Criteria Document provides ample support for the Administrator's findings. 69 The Criteria Document concluded that EP elevation, which begins in children at blood levels of 15-20 ug Pb/dl, is one of the more significant effects of low level lead exposure because it indicates that lead has already begun to affect basic biological functions in the body. We have already examined in some detail the findings that led the Criteria Document to the conclusion that EP elevation is an indication of a physiological impairment which affects human health. 57 Briefly stated, it concluded that EP elevation indicates an impairment of the functioning of the mitochondria 58 ; that EP elevation indicates that lead has begun to affect the process of heme synthesis; that EP elevation may indicate a reduction in any reserve capacity there might be in the heme synthesis system; and that lead's impairment of heme synthesis in the blood suggests that lead may also interfere with production of heme proteins in other organ systems. Relying on the Criteria Document's discussion, as well as other evidence in the record, the Administrator made a judgment that for purposes of setting air quality standards for lead, EP elevation at 30 ug Pb/dl must be considered the first adverse effect on the health of children, and he determined that the maximum safe individual blood lead level should be no higher than 30 ug Pb/dl. 70 The Administrator's judgment echoes the consensus of a group of clinicians who, in 1975, participated in preparation of a statement issued by the Center For Disease Control and endorsed by the American Academy of Pediatrics. These experts agreed that EP elevation should be used as an indicator of a significant and worrisome body burden of lead. CD 11-14, JA 1236. Moreover, the Center For Disease Control uses EP elevation at 30 ug Pb/dl as the cutoff point for detection of lead poisoning in children in its screening programs, 59 a factor that influenced the Administrator's decision. 43 Fed.Reg. 46253, JA 2955. The Administrator's reliance on this was, in our view, entirely appropriate. While the Center has indicated that children with a blood lead concentration of 30 ug Pb/dl have a lead problem, 60 it is also significant that the Center's screening program has much the same preventive and precautionary approach that Congress directed the Administrator to apply to the task of setting air quality standards designed to protect the public health. 61 Further support for the Administrator's decisions is provided by the testimony of various medical and other scientific experts who participated in the lead standards rulemaking. These experts endorsed the Administrator's (and Criteria Document's) conclusions about the effects of low level lead exposures, and agreed with his assessment of the health significance of these effects. 62 The Administrator's decision is, of course, precisely the sort of issue that Congress specifically left to his judgment, and where there is evidence in the record which supports these judgments, this court is not at liberty to substitute its judgment for the Administrator's. In this instance the Administrator has acted properly under the terms of the statute. He has explained his factual findings and policy judgments, and there is an adequate basis in the record for these decisions. No more is required of him. 71 LIA's challenge to the Administrator's findings concerning the health significance of EP elevation also stresses that this phenomenon is only a subclinical effect. But the clinical/subclinical distinction has little to do with the question whether a particular effect is properly viewed as adverse to health. Rather, the distinction pertains to the means through which the particular effect may be detected: observation or physical examination in the case of clinical effects, and laboratory tests in the case of subclinical effects. 63 Thus describing a particular effect as a subclinical effect in no way implies that it is improper to consider it adverse to health. 64 While EP elevation may not be readily identifiable as a sign of disease, the Administrator properly concluded that it indicates a lead-related interference with basic biological functions. Expert medical testimony in the record confirms that the modern trend in preventive medicine is to detect health problems in their subclinical stages, and thereupon to take corrective action. 65 Moreover, as we have already noted, the Center For Disease Control uses the same subclinical effect as the key indicator of the need for medical intervention in its lead poisoning screening program. The accepted use of this subclinical effect to determine the need for medical observation or intervention properly influenced the Administrator's decision. 66 Thus the fact that the effects the Administrator relied on in setting the lead standards are subclinical does not detract from their significance for human health, or make them an improper basis for setting air quality standards. 72 We also reject LIA's claim that the evidence in the record does not support the Administrator's determination that the blood lead threshold for symptoms of anemia in children is 40 ug Pb/dl. According to the Criteria Document, the onset of anemia is marked by a decline in the level of hemoglobin per unit of blood, CD 13-4, JA 1334. And the Criteria Document states that (r)eports on children indicate that statistically significant decreases in hemoglobin levels begin to appear at a blood lead level of 40 ug (Pb)/dl or somewhat below. Id. At another point the Criteria Document explains, In children, a threshold blood lead level for production of    symptoms of anemia is approximately 40 ug Pb/dl   . CD 1-6, JA 1110. See id. 11-13, JA 1235; JA 2583-2585 (Needleman and Piomelli). The Criteria Document's conclusions were reached after a review of various studies that have examined the subject, and we cannot, in light of these findings, say that the Administrator's decision about the threshold blood lead level for the symptoms of anemia in children does not have an adequate basis in the record. 67 73 Finally, our examination of the record also reveals ample support for the Administrator's determination that lead-induced central nervous system deficits begin to occur in children at blood lead levels of 50 ug Pb/dl. The central nervous system damage about which the Administrator was concerned was not the severe brain damage that can occur at relatively high levels of lead exposure 80-100 ug Pb/dl. 68 Rather, his focus was on more subtle and largely irreversible neurological and behavioral impairment that has been detected in children at lower blood lead levels, 43 Fed.Reg. 46253, JA 2955. 69 The Criteria Document candidly admitted that (t)he literature on this subject is somewhat limited and controversial, but it was nevertheless able to conclude that certain statements (can) be made about the possible hazard of low to moderate lead exposure levels. CD 11-18, JA 1240. The conclusion it reached, after a detailed review of various studies that have examined the subject, was that: 74 (The) evidence tends to confirm that some type of neural damage does exist in asymptomatic children, and not necessarily only at very high level of blood lead. The body of studies on low- or moderate-level lead effects on neurobehavioral functions    present overall a rather impressive array of data pointing to that conclusion. Several well-controlled studies have found effects that are clearly statistically significant, whereas others have found nonsignificant but borderline effects. Even some studies reporting generally nonsignificant findings at times contain data confirming statistically significant effects, which the authors attribute to various extraneous factors.    75 CD 11-26, JA 1248. The Criteria Document reported that the blood lead levels associated with these neurobehavioral deficits are 50-60 ug Pb/dl. Id. These conclusions were endorsed by several of the experts who participated in the lead standards rulemaking proceedings, including one of LIA's experts. 70 Some of these experts even suggested that these effects may occur at blood lead levels lower than the levels indicated by the Criteria Document. 71 Contrary to LIA's suggestion, the evidence in the Criteria Document and the testimony of the experts provides an adequate basis for this court to undertake a review of the Administrator's findings concerning these effects. Accordingly, we reject LIA's challenge to the Administrator's conclusion that central nervous system deficits begin to occur in children at blood lead levels of 50 ug Pb/dl. 76 Our conclusion that there is ample support for the Administrator's determination that EP elevation at 30 ug Pb/dl is the first adverse health effect that children experience as a result of lead exposure is, of course, sufficient to sustain his selection of 30 ug Pb/dl as the maximum safe individual blood lead level. Given this, we cannot say that his further determination that a maximum safe individual blood lead level of 30 ug Pb/dl would in addition provide protection against the more serious adverse health effects of lead exposure was irrational. 77 To be sure, the Administrator's conclusions were not unchallenged; both LIA and the Administrator are able to point to an impressive array of experts supporting each of their respective positions. 72 However, disagreement among the experts is inevitable when the issues involved are at the very frontiers of scientific knowledge, and such disagreement does not preclude us from finding that the Administrator's decisions are adequately supported by the evidence in the record. It may be that LIA expects this court to conclude that LIA's experts are right, and the experts whose testimony supports the Administrator are wrong. 73 If so, LIA has seriously misconceived our role as a reviewing court. It is not our function to resolve disagreement among the experts or to judge the merits of competing expert views. AFL-CIO v. Marshall, 617 F.2d 636, 651 & n.66 (D.C.Cir.1979); cf. Hercules Inc. v. EPA, 598 F.2d 91, 115 (D.C.Cir.1978) ((c)hoice among scientific test data is precisely the type of judgment that must be made by EPA, not this court). Our task is the limited one of ascertaining that the choices made by the Administrator were reasonable and supported by the record. Ethyl Corp. v. EPA, supra, 541 F.2d at 35-36. That the evidence in the record may also support other conclusions, even those that are inconsistent with the Administrator's, 74 does not prevent us from concluding that his decisions were rational and supported by the record. AFL-CIO v. Marshall, supra, 617 F.2d at 651 n.66; Environmental Defense Fund, Inc. v. EPA, 510 F.2d 1292, 1298 (D.C.Cir.1975); accord, Bayside Enterprises, Inc. v. NLRB, 425 U.S. 298, 302, 97 S.Ct. 576, 579, 50 L.Ed.2d 494 (1976). Cf. Universal Camera Corp. v. NLRB, 340 U.S. 474, 488, 71 S.Ct. 456, 465, 95 L.Ed. 456 (1951) (a court may (not) displace the (agency's) choice between two fairly conflicting views, even though the court would justifiably have made a different choice had the matter been before it de novo ). 78 Having determined that we must uphold the Administrator's decisions concerning the health effects that are the basis for the lead standards, we turn to petitioners' other challenges to the Administrator's analysis.