Environmental Protection Agency (EPA) Administrator Gina McCarthy on December 19, 2014, signed a proposed rule that would retain, without revision, the national ambient air quality standards (NAAQS) for lead of 0.15 micrograms per cubic meter (ug/m3). The rule should be published in the Federal Register soon. EPA states that the existing primary (health based) standard provides health protection for at-risk groups, especially children, and the existing secondary (welfare based) standard provides protection against adverse effects to public welfare, including harm to aquatic and terrestrial ecosystems.

The Clean Air Act (CAA) requires EPA to set NAAQS for criteria pollutants (lead, ozone, nitrogen oxides, carbon monoxide, sulfur oxides, and particulate matter) and to review the standards every five years. In EPA’s prior review of the lead NAAQS, completed in 2008, EPA significantly strengthened the standard based on a dramatic expansion and greater understanding of the scientific evidence about lead and health that had occurred since EPA issued the initial standard in 1978. The evidence from health studies available in the 2008 review showed that adverse effects occur at much lower levels of lead in blood than had been previously thought. In the current proposal, EPA states that “the evidence available in this review is consistent with the EPA Administrator’s conclusions in the last review. The health effects evidence continues to support the conclusion that lead damages developing nervous systems in young children. In addition, lead can damage cardiovascular and reproductive systems and red blood cell production.” EPA specifically proposes to retain the current standard of 0.15μg/m3 (as a three-month average in total suspended particles).

EPA concludes that the current standard provides protection of public health with an adequate margin of safety. The standard provides protection for children and other at-risk populations against a variety of adverse health effects, most notably effects on the developing nervous system. EPA also proposes to retain the current secondary standard, which is identical to the existing primary standard. EPA concludes that the current standard “provides the requisite protection from adverse environmental effects to public welfare, including effects on aquatic and terrestrial ecosystems. Currently there are 21 areas designated as nonattainment for the 2008 lead NAAQS.

EPA will accept comments on the proposed rule for 90 days after it is published in the Federal Register.