Dr. Linda Birnbaum is an unsung hero of the modern environmental movement. For 33 years, she's been a leading researcher and writer on environmental toxicology issues, advancing understanding of specific poisons as well as the cumulative impact of the thousands of chemicals we're exposed to in daily life. First at the EPA, and now at the National Institute of Environmental Health Services, she's been at the leading edge of US environmental health research. Scientific American recently did a sit down interview with Birnbaum to talk about her work. Go and get caught up on why we can't trust current "safe" levels of much of anything.