NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.

This project between the National Academy of Sciences and U.S. Consumer Product Safety Commission (CPSC) was supported by Contract No. CPSC-C-99–1152. This report was prepared by the National Research Council as a result of a direction in the fiscal year 1999 appropriations for the United States CPSC. The views expressed in the report do not necessarily represent the views of CPSC.