In November 2018, the record-breaking Camp Fire consumed over 18,000 industrial and residential structures in the town of Paradise, California. After the blaze was contained, California State University, Chico water-quality engineer Jackson Webster’s group sprang into action, gathering samples from the area’s creeks. They hoped to answer a question looming over water-quality chemists as wildfires become more frequent and intense: after an entire town burns, what chemicals end up in nearby bodies of water? At the American Chemical Society national meeting in San Diego last week, Webster presented some initial answers. Compared with watersheds that do not drain from areas that burned, creeks draining from Paradise showed significantly higher levels of nitrogen. Webster said that septic tanks, which the town’s residents relied on instead of a sewage system, burned and left large holes in the ground. He suspects that rain draining from the holes likely carried nitrates into area creeks. Webster’s team also found per- and polyfluoroalkyl substances (PFAS) and other organic chemical contamination. Pentachlorophenol levels of 1–2 micrograms per liter are “the clearest indicator of urban burn,” Webster said. The chemical is used to treat wood, including utility poles. The data are not yet complete, however, Webster said. He’s still waiting on results of tests for toxic metals that might have come from, for example, the melted lead batteries of tens of thousands of burned cars.