The D.C. police internal affairs division is investigating an incident in which burning police and fire department personnel documents were allegedly discovered in dumpsters at the fire department’s training academy Friday.

Firefighters found the documents when they were dispatched to the training academy about 5 p.m., according to a letter written jointly by the police and firefighter unions that asked D.C. Inspector General Charles J. Willoughby to investigate.

Firefighters found burning documents in three dumpsters and unburned documents that had been blown away by wind, the letter says.

The documents included sensitive information such as addresses, Social Security numbers and medical records, according to the letter.

Some of the documents were nearby in an abandoned car, the letter says.

“Members of FEMS [Fire and Emergency Medical Services] were able to identify their own training and medical records in the abandoned car,” the letter says.

D.C. police released a statement Wednesday saying the department had launched an investigation.

“Once this matter was brought to our attention, our Internal Affairs Division immediately began investigating,” the statement says. “We are looking into whether any records retention protocols have been violated. The Metropolitan Police Department will cooperate with the Office of the Inspector General during the course of their investigation.”

Willoughby’s office would neither confirm nor deny an investigation Wednesday.

“This is very serious, and they need to look into it,” said Edward Smith, president of the D.C. Firefighters Association. “I don’t know how they can walk away from it.”

The letter to Willoughby, signed by Smith and Kristopher Baumann, chairman of the D.C. police union, said the city’s mishandling of the documents violated D.C. law.

“It is simply beyond comprehension that this is how records are being handled by the District of Columbia Government,” the letter says.