KEENE, N.H. (MyKeeneNow) Lt. William “Bill” Shea is back home in Keene after spending two weeks hospitalized with injuries he suffered in a powerful natural gas explosion that destroyed a Nashua mental health facility earlier this month.

Shea, a more than 20-year veteran of the Nashua Fire Department, was released Sunday from Southern New Hampshire Medical Center, making him the final of three injured firefighters to leave the hospital following the Feb. 2 blast at Greater Nashua Mental Health.

Fire officials have said all three firefighters sustained injuries considered non-life-threatening. Nashua Fire Chief Steve Buxton told WMUR-TV that Shea is expected to be out of work for an extended period but is anticipated to make a full recovery.

The explosion occurred just minutes after crews responded to the mental health center for a reported odor of gas. About 40 people were inside the building at the time. All occupants were able to evacuate safely before the blast.

Firefighters were still investigating the source of the leak when the explosion rocked the building and triggered a large fire. Part of the structure began to collapse as flames tore through the facility, which was ultimately destroyed.

Authorities sent emergency alerts to nearby homes and businesses advising residents to extinguish open flames and prepare to evacuate. Witnesses less than a half mile away reported feeling their homes shake from the force of the blast.

The cause of the gas leak remains under investigation by the National Transportation Safety Board.

Shea, a graduate of Keene State College, previously served on the Keene Fire Department from 1999 to 2004. In addition to his work in Nashua, he owns a fire service education company and is well known in the Monadnock Region firefighting community.

Gov. Kelly Ayotte, a Nashua native, said earlier this month she had been briefed on the explosion and praised the swift actions of firefighters and first responders.

Nashua, located about 45 miles north of Boston, has experienced an extended stretch of bitter cold in recent weeks, conditions that fire officials said complicated efforts to bring water to the flames.

While recovery efforts continue and investigators work to determine what caused the rupture, Shea’s return home marks a significant milestone in the aftermath of one of the city’s most dramatic emergency incidents in recent years.