States target toxic tire compound

Two West Coast states, Washington and California, are making efforts to limit the amount of N -(1,3-dimethylbutyl)- N ′- phenyl- p -phenylenediamine, known as 6PPD, that gets into the environment. Tire makers add 6PPD to rubber to protect it from damage caused by reacting with ozone and other oxygen compounds. However, when 6PPD reacts, it forms another chemical called 6PPD-quinone. This byproduct can kill coho salmon within hours of entering streams near roads, and it can be deadly to other fish within days. In mid-August, Washington became the first US state to limit the amount of 6PPD-quinone that can be present in water. Washington updated its water quality rules based on the latest scientific research, new testing methods, and guidance from the US Environmental Protection Agency and tribal governments. The new rules, which also set limits for other chemicals including perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and aluminum, will start