UPDATED: Chemical Explosion Investigation at Dow Industrial Plant

Photo Credit: 7News/whdh.com

NORTH ANDOVER, MA - Investigators continued their work Friday afternoon to determine what happened to cause the massive chemical explosion at Dow on Willow Street.

Five people were injured in the explosion, four critically. Four of the five were hospitalized, and the fifth person was treated at the scene.

The cause of the incident was still not known by noon, according to a company spokesperson. The spokesperson said the investigation is proceeding with the Dow’s full cooperation and participation.

State and federal officials resumed their investigation early Friday into the explosion that occurred about 2:30 Thursday afternoon in a chemical lab. The state’s bomb squad will detonate some of the dangerous chemicals that injured workers, according to 7News/whdh.com.

Emergency personnel are also working at the facility to ensure all safety and regulatory requirements are met, according to a company spokesperson.

The critically injured workers suffered shrapnel injuries and burns, according to Lawrence General General Hospital officials. The patients and firefighters were decontaminated.

According to cbslocal.com, an emergency room physician at Lawrence Memorial Hospital says the victims are suffering from burns related to the blast involving the chemical trimethylaluminum.

Trimethylaluminum is a key ingredient in making LED lights. DOW develops materials that are used in LED light manufacturing.

The common name, trimethyl aluminum, is a colorless liquid. The chemical is highly flammable and reactive, and a fire and explosion hazard, according to the New Jersey Department of Health and Senior Services Hazardous Substance Fact Sheet.

A worker was killed in a chemical explosion at the same plant in 2013. The cause of the explosion in 2013 was exposure of Trimethylindium, a pyrophoric chemical, to the air.

Fire equipment also had to be decontaminated, according to fire officials. North Andover firefighters were stationed throughout the night at the site.

The North Andover plant is located about 25 miles north of Boston.

Sign up for North Andover news alerts, follow North Andover Patch on Facebook, and send news tips to linda.bock@patch.com.

Refresh your browser for updated information as it becomes available.