An American Airlines flight had just unloaded passengers at Miami International Airport due to a maintenance issue when the pilot, Ronald Weiland, noticed thick fog filling the cabin of the Boeing 767-300. A maintenance technician shut off the auxiliary power unit in the tail of the aircraft, which cleared the air, but Weiland’s eyes burned and his throat was dry.

He went home to tell his wife but didn’t think much of it until, months later, he had difficulty speaking then swallowing and was ultimately diagnosed with Lou Gehrig’s disease. Nearly a year later, after talking to his brother, a Jet Blue pilot, he alerted the chairman of the Airline Pilots Association’s Safety Committee about the “fume event” and submitted an injury report.