A review of available sources did not identify acute toxicity data or exposure limits for lead hydroxide. Instead, analysts evaluated exposure limits for lead (TWAs, STELs, IDLHs; CASRN: 7439-92-1) for TEEL development. Data sources were selected according to the hierarchy listed in Table 3.1. Toxicity data were selected according to type of exposure, species, and route according to the hierarchies stated in Sections 3.3.1, 3.3.2, and evaluated using factors in Tables 3.2, 3.3, and 3.4. Analysts selected the 1990 lead IDLH (CASRN: 7439-92-1) as the TEEL-3 basis and a compound adjustment factor was applied (Section 3.2.2). The TEEL-2 was derived according to Table 3.5. The MAK-STEL for inorganic lead compounds (CASRN: 7439-92-1, Germany DGF, inhalable fraction, 15-minute) was selected as the TEEL-1 and a compound adjustment factor was applied (Section 3.2.2).
• PAC-1 = TEEL-1 = MW-adjusted MAK-STEL (inorganic lead compounds, CASRN: 7439-92-1; 0.032 mg/m3)
• PAC-2 = TEEL-2 = TEEL-3/6
• PAC-3 = TEEL-3 = MW-adjusted IDLH (1990, lead, CASRN: 7439-92-1; 700 mg/m3)
This review generated PAC-3 and PAC-2 values consistent with Rev. 29A and PAC-1 inconsistent. The Rev. 29A and current TEEL-3 use the same source and methodologies. The Rev. 29A and current TEEL-2 use the same source and methodology. The Rev. 29A TEEL-1 basis was a weight adjusted TLV-TWA, while the current TEEL-1 is a weight adjusted MAK-STEL (Table 3.1).