Lead Human Exposure and Health Risk Assessments for Selected ...

PREFACE
This document is part of the Environmental Protections Agency’s (EPA’s) review of the
National Ambient Air Quality Standards (NAAQS) for lead (Pb). As part of that review, the
Agency has prepared the Air Quality Criteria Document for Lead (the “CD”, October, 2006;
available at http://www.epa.gov/ttn/naaqs/standards/pb/s_pb_cr_cd.html), a draft Staff Paper
(Review of the National Ambient Air Quality Standards for Lead: Policy Assessment of Scientific
and Technical Information, OAQPS Staff Paper – First Draft, December, 2006; available at
http://www.epa.gov/ttn/naaqs/standards/pb/s_pb_cr_sp.html), and a draft technical report of pilot
phase risk assessments (Lead Human Exposure and Health Risk Assessments and Ecological
Risk Assessment for Selected Areas, December, 2006; available at
http://www.epa.gov/ttn/naaqs/standards/pb/s_pb_cr_td.html). These documents were developed
under our historic approach for reviewing NAAQS, which has included the completion of a
policy assessment, in the form of a Staff Paper, and of any related risk and exposure assessments
(risk/exposure reports) prior to development of notices of proposed and final rulemakings. The
policy assessment, considering the adequacy of the current standard and policy alternatives, is
intended to help “bridge the gap” between the scientific assessment contained in the CD and the
judgments required of the EPA Administrator in determining whether it is appropriate to retain
or revise the NAAQS.
The Agency is now moving forward to implement a new, improved process for
conducting NAAQS reviews (http://www.epa.gov/ttn/naaqs/) and is transitioning to that new
process during the course of the Pb NAAQS review, beginning with this document (the
risk/exposure report). Under the new process, the risk/exposure report precedes the policy
assessment (rather than accompanying it), and the policy assessment is included in an Advance
Notice of Proposed Rulemaking (ANPR) rather than a Staff Paper. Accordingly, it is the
Agency’s intention that the results of the assessments described in the final risk/exposure
assessment report for Pb will be considered, in combination with an evaluation of the policy
implications of the key studies and scientific information contained in the CD and ambient Pb
analyses, in the development of the policy assessment to be published in the Federal Register in
an ANPR this fall. 1
Volume I of this document has been drafted by EPA staff, and the appendices (contained
in Volume II) have been drafted by EPA staff, in conjunction with ICF International (through
Contract No. EP-D-06-115). This draft document is being provided to the Clean Air Scientific
Advisory Committee (CASAC) for their review, and is being made available to the public for
1 EPA’s preference is to issue the policy assessment as part of an ANPR and not in the form of a final Staff
Paper. EPA is currently, however, under a court order to issue a final Staff Paper and has moved for modification of
that order to allow EPA to issue an ANPR in place of a final Staff Paper. In the event EPA’s motion is not granted,
EPA intends to fully comply with the existing order.