Powerful explosion at Massachusetts pharmaceutical plant sends 4 to hospital, 1 worker left unaccounted for

A powerful explosion at a pharmaceutical plant in Massachusetts that has a checkered history left one worker missing, sent four people to the hospital and blew an industrial-sized vat into a parking lot, officials said Thursday.

The explosion happened around 1 a.m. at the Sequens/PCI Synthesis plant in Newburyport, officials said. Video footage showed most of the roof torn off a building, and the blast blew a vat from inside the building 30 feet into a parking lot, acting Fire Chief Stephen Bradbury III said in a news release.

It wasn’t immediately known what caused the explosion, and it wasn't clear what role, if any, the vat played in the explosion.

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"There is major structural damage to the building, preventing firefighters and technical rescue crews from entering the building to begin a search," Bradbury said.

There is no danger to nearby homes, he said, but workers at the industrial park where the plant is located were asked to avoid the area.

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The four workers were sent to the hospital as a precaution, were not injured and were released. But one worker was not yet accounted for.

"All our attention is focused on the situation of our employees," a company statement said.

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In 2020, authorities said a chemical reaction caused a series of explosions at the plant. That happened a year after the Occupational Safety and Health Administration found "serious" violations in the company’s management of highly hazardous chemicals, according to online agency records.