Florida International University scientists have, for the first time, detected a toxic tire-derived chemical in Florida waterways and developed a new testing method that makes it easier to find and monitor the pollutant at extremely low levels. The study focuses on 6PPD-quinone (6PPD-Q), a toxic chemical formed when the tire additive 6PPD reacts with ozone in the atmosphere. The compound has been linked to fish deaths in other parts of the country and is drawing increasing concern among environmental scientists.