The Boston fire commissioner is retiring after 36 years at the department, he announced Monday.

Joseph Finn, 56, wrote on his official Twitter account that he will retire on March 12. Throughout his career, Finn held every rank, including the past five years as the department's leader, The Boston Globe reported.

Under Finn's leadership, the Boston Fire Department put a renewed focus on safety and reducing cancer rates among firefighters who are exposed to toxic chemicals.

In a tweet, Mayor Marty Walsh thanked Finn for his years as a firefighter and said he plans to name Finn's successor in the "coming days."

"His steadfast commitment to the men and women of the fire department never wavered, and for that, the City of Boston is grateful," Walsh tweeted.