Galassia Grassetto thought she had moved to a quiet, safe California neighborhood. Through an odd smell she followed from her house to the surrounding streets, she learned what lay beneath it: treated sewage sludge, the material regulators and industry call biosolids and spread on farm fields, parks and gardens across the country. Supporters say land application returns valuable nutrients to the soil. Grassetto wanted to know what else comes with them. Her questions turned into a five-year, ten-state investigation.

Drawing on never-before-seen depositions, insiders willing to talk and scientists who have spent decades studying the material, she traces how a waste-disposal problem came to be marketed and sold as fertilizer and compost, and why communities from California to upstate New York are pushing back. A determined work of citizen-led reporting, The Sludge War asks what happens when the people living with the consequences are the last to learn the facts, and what it takes to get them.