NASHUA, N.H. (PulseWire) — A significant explosion at a mental health center in Nashua, New Hampshire, occurred due to a natural gas leak, injuring three firefighters while all building occupants were safely evacuated on Monday.

The Greater Nashua Mental Health facility had around 40 people present when an odor of gas was reported, leading to a 911 call. Firefighters were conducting initial investigations when the explosion took place, resulting in part of the structure collapsing, according to State Fire Marshall Sean Toomey and Nashua Fire Chief Steve Buxton.

The injured firefighters received medical attention at a local hospital for non-life-threatening injuries. Witness accounts describe the blast as powerful enough to shake houses in nearby neighborhoods, with one resident, Jesci Larochelle, stating it felt like a tree had fallen onto her home.

The incident necessitated immediate alerts being sent to nearby residences and businesses, advising them to extinguish any flames and prepare for potential evacuation due to safety concerns.

The facility, located on a busy road, offers crucial services including substance misuse support and services for deaf and older adults. Aerial footage shown by local news outlets revealed extensive flames and smoke erupting from the rubble, with debris scattered across the area.

Governor Kelly Ayotte expressed her gratitude toward firefighters and first responders, acknowledging their heroic efforts amidst the challenging circumstances, especially given the extreme cold weather affecting firefighting operations.

This incident follows a tragic explosion at a nursing home in Pennsylvania last year, which resulted in fatalities and sparked ongoing investigations. The Nashua explosion highlights the need for vigilance in gas leak safety measures as authorities continue their responses.