Dow Chemical
A Dow Chemical plant in North Andover, Massachusetts exploded on 7 January, injuring at least five Getty Images

Several people were injured in a chemical explosion at the Dow Chemical plant in North Andover, Massachusetts on 7 January with at least five people injured being taken to hospital.

"We are aware of five injuries, at least one critical injury, all have been transported," North Andover Town Manager Andrew Maylor said. Fire officials said that three of those injured were flown hospitals in Boston which is about 30 miles away.

According to CBS Boston, emergency crews responded to the chemical facility around 2.30pm EST (7.30pm GMT). Maylor told reporters that there was no threat to residents and businesses and that chemicals were not released into the air.

"Whatever caused the explosion has been addressed, so there is not a current risk, whether that results in the need for a cleanup, I think that's why state officials are on site to address that," Maylor said.

Authorities are investigating the cause of the explosion. Fox News reported that the incident is being investigated by the fire investigation unit, the bomb squad and a state Hazmat team. A chemical explosion at the same Dow Chemical plant in 2013 led to the death of one worker.