Nashua gas leak: Massive fire, explosion at Amherst Street; videos show scary scenes- Watch

A 4-alarm fire and explosion from a gas pipeline leak hit a building on Amherst Street in Nashua, NH, prompting a massive emergency response.

A 4th alarm fire erupted at a building on 4400 Amherst Street in Nashua, New Hampshire on Monday afternoon after a gas leak. Nashua Fire Rescue confirmed that an explosion tool place from a gas pipeline leak. A massive emergency response was underway.

Representational. (Unsplash)

Videos from the scene of the explosion and fire emerged which showed fire crews battling flames.

Later, in an update, the Nashua Fire Rescue provided further details on the incident. Local newspaper Union Leader reported that firefighters responded to the building- the mental health hospital Greater Nashua Mental Health, following a gas leak.

As they arrived, an explosion occurred in the building, even as 40 employees were still inside the building.

Now, the building has been evacuated, and the Union Leader reported that all the employees trapped in the fire are accounted for, per Nashua Fire Chief Steve Buxton.

The cause of the fire is unknown. Nashua Fire Rescue has said that they will investigate the site when the fire is completely out.

Residents have been asked to avoid the area as the response and investigation continue.