More than 120 fires have occurred in the past five years, including 12 in the first four months of this year. News and social media photos show the trucks burning intensely, often inches away from trees, cars and, in one case, a gasoline pump in Connecticut.
The incidents of mail trucks fires are on pace this year to double the number that occurred last year. At least one injury, a letter carrier burning his hand, is linked to the fires.
But the U.S. Postal Service keeps operating its fleet of 140,000 custom-made Grumman Long Life Vehicles. It declined to answer Trucks.com requests for information about the causes of the fires and its actions to remedy the problem. The average age of the trucks is now 27.5 years.
The Postal Service hired an engineering firm in 2014 to investigate the cause of the fires. When no single reason was discovered, the agency increased efforts to stick to mandated maintenance schedules and fine-tune repair and maintenance procedures, according to agency memos.
The Postal Service declined to comment on the potential public safety hazard posed by the fires. It also declined to say how many fires have occurred. And it declined to comment on whether it has discussed the fires with Morgan Olson LLC, a successor company to the original manufacturer.