EPA IRIS — Lead, Oral RfD and Carcinogenicity Assessment

Overview

The EPA Integrated Risk Information System chemical assessment for inorganic lead does not derive a quantitative oral reference dose (EPA IRIS Pb 2004). The oral RfD section of the IRIS file (Section I.A.) contains a qualitative discussion only, last revised 2004-07-08, on the basis that available data do not support a traditional threshold-based RfD derivation for lead’s most sensitive endpoint (developmental neurotoxicity in children). The inhalation RfC (Section I.B.) is not evaluated. The carcinogenicity assessment (Section II.) was last revised 1988-09-26 and classifies inorganic lead as B2 (probable human carcinogen) based on animal evidence with inadequate human evidence; no cancer slope factor or unit risk is derived (EPA IRIS Pb 2004).

EPA’s operational position parallels JECFA’s 2010 withdrawal of the PTWI (JECFA 73rd 2010) and EFSA’s 2010 conclusion (EFSA Pb 2010): lead has no demonstrated effect threshold for the most sensitive endpoint, so traditional reference-value methodologies do not apply (EPA IRIS Pb 2004). US lead regulatory action operates through CDC blood lead reference values (CDC BLRV), FDA Closer to Zero Interim Reference Levels, and matrix-specific FDA action levels (FDA CTZ Pb 2025) rather than through an IRIS-derived oral RfD.

Assessment status

Assessment status from EPA IRIS Pb 2004:

Sources

• EPA IRIS Pb 2004 — EPA IRIS Chemical Assessment Summary, Lead and Compounds (Inorganic), CASRN 7439-92-1.

References

Works cited in this page’s text, in first-appearance order. See Sources for this page’s source inventory. Each title links to its source record, which carries the ingest receipt, the extracted values, and the file hash of the document it was built from.

1. Lead and Compounds (Inorganic) — IRIS Chemical Assessment SummaryU.S. Environmental Protection Agency, National Center for Environmental Assessment · U.S. Environmental Protection Agency, Integrated Risk Information System · 2004 · iris.epa.govGovernment
2. Lead (Addendum), 73rd Meeting of the Joint FAO/WHO Expert Committee on Food Additives — Safety Evaluation of Certain Food Additives and ContaminantsJoint FAO/WHO Expert Committee on Food Additives · WHO Technical Report Series 960 (2011); lead addendum in WHO Food Additives Series No. 64 · 2011 · www.who.intGovernment
3. Scientific Opinion on Lead in FoodEFSA Panel on Contaminants in the Food Chain (CONTAM) · EFSA Journal 2010;8(4):1570 · 2010 · doi.org/10.2903/j.efsa.2010.1570Government
4. Blood Lead Reference Value (3.5 µg/dL)U.S. Centers for Disease Control and Prevention · 2021 · www.cdc.govGovernment
5. Action Levels for Lead in Processed Food Intended for Babies and Young Children: Guidance for IndustryU.S. Food and Drug Administration · U.S. Department of Health and Human Services, Food and Drug Administration, Human Foods Program · 2025 · www.fda.govGuidance

Update history

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