An introduction to a series of U.S. Environmental Protection Agency special committee reports on testing approaches for the detection of chemically induced aneuploidy.

A committee of scientists was established by the U.S. Environmental Protection Agency to appraise the current state of aneuploidy test methodology, to compile and analyze published data on the chemical induction of aneuploidy, and to provide guidance for additional test development and validation. The reports that follow in this special issue of Mutation Research, document the urgent need for test method development and validation in this important area of environmental mutagenesis, and provide directions for further research.