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

Heading: Air Lead/Blood Lead Ratio

Text: 87 LIA contends that the Administrator's choice of an air lead/blood lead ratio of 1:2 as the appropriate ratio for calculating the lead standards was arbitrary and capricious. LIA's claim is largely based on its disagreement with the Administrator's interpretation of the results of three studies that have examined the relationship between air lead exposure and blood lead levels. It argues that the Administrator's analysis of these studies is inconsistent and designed solely to support his decision to arrive at an air quality standard of 1.5 ug Pb/m 3. 83 In addition, LIA contends that the Administrator erred by calculating the air lead/blood lead ratio on the basis of studies involving both adults and children, when the standards are designed to protect children. LIA maintains that the Administrator would have arrived at a ratio of 1:1.3, had he focused solely on the studies involving children. 88 We do not agree that the Administrator's selection of an air lead/blood lead ratio of 1:2 was arbitrary or capricious. The Criteria Document reported that air lead/blood lead ratios for the whole population, adults as well as children, range between 1:1 and 1:2, with children at the upper end of the range or even slightly above it. CD 12-38, JA 1325. And the range of ratios for children reported by the studies that were reviewed in the Criteria Document was 1:1.2 to 1:2.3, CD 12-25 (Table 12-28), JA 1312 (Table 12-28). 84 The Administrator's choice of a ratio of 1:2 for purposes of calculating the lead standards is consistent with each of these findings. Moreover, the Administrator calculated that each of three particularly relevant and well-documented studies that were reviewed by the Criteria Document suggested an air lead/blood lead ratio close to 1:2. 43 Fed.Reg. 46250, 46254, JA 2954, 2956. 85 Finally, the Administrator's choice of a ratio of 1:2 was endorsed by several experts who participated in the rulemaking proceedings. 86 Indeed, the issue of the proper relationship between air lead exposure and blood lead levels was extensively discussed in the comments on the initial drafts of the Criteria Document, with several experts severely criticizing the suggestions in early drafts that the appropriate ratio is 1:1. 87 Given all the evidence in the record which supports the Administrator's choice of a ratio of 1:2, we would be exceeding the scope of our reviewing function if we were to agree with LIA's suggestion that the Administrator's decision was either arbitrary or capricious. 88