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Investigation continues into deadly Newburyport pharmaceutical plant explosion

Mayor Sean Reardon said in an e-mail Sunday night that officials hope to demolish the part of the building damaged by the blast by the end of Monday.

Firefighters on the site of a deadly explosion at the PCI Synthesis plant in Newburyport Thursday.Josh Reynolds for The Boston Globe

Authorities continued their investigation Sunday into the cause of an explosion at a pharmaceutical plant in Newburyport last week which killed one worker, sent four other employees to the hospital, and triggered a massive response by state and federal agencies.

The early morning blast Thursday at the PCI Synthesis facility was powerful enough to shake nearby homes, and blow a large industrial vat through the building’s roof and land about 30 feet away in a parking lot, officials have said.

Newburyport Mayor Sean Reardon said in an e-mail Sunday night that officials hope to demolish the part of the building damaged by the blast by the end of Monday.


A preliminary investigation shows the explosion appears to be related to a chemical manufacturing process and does not appear suspicious, according to Jake Wark, spokesman for the state Department of Fire Services.

State hazmat crews completed their work at the blast site and removed several dozen drums containing chemicals used at the plant, including from the damaged plant structure on Friday, Wark said in an e-mail to the Globe.

The explosion also sparked a seven-alarm fire, and crews from Newburyport and several area communities in the Merrimack Valley.

Jack O’Keefe, a 62-year-old from Methuen, was identified by the Essex district attorney’s office as the plant employee killed in the blast. The injured workers were treated at Anna Jaques Hospital and released, officials have said.

The cause of the blast is being investigated by the Newburyport Fire Department, along with State Police assigned to the state fire marshal’s office and the Essex district attorney’s office. The state Medical Examiner’s office was expected to conduct an autopsy on O’Keefe’s body.

Officials from the state Department of Environmental Protection; the US Occupational Safety and Health Administration; and the Environmental Protection Agency also responded to the scene.


Newburyport firefighters and state hazmat crews remained at the scene overnight Thursday and into Friday to monitor the site, while air meters were erected around the site’s perimeter, but no hazards were detected.

The France-based Seqens, in a statement late Thursday, has said that the safety of its employees is the company’s top priority.

“We strive to follow best practices and regulatory guidelines, and have implemented safety protocols and procedures to prevent incidents like this from occurring,” the statement said.

The factory has faced numerous citations and fines from federal regulators over safety incidents.

Reardon will order the plant shut down until investigators determine a cause for the blast. He told the Globe that Thursday’s explosion and fire was the third emergency in three years at the facility.

In June 2021, a blaze erupted after chemicals caught fire at the plant. And in early 2020, a series of chemical explosions ripped through the building. No injuries were reported in either incident.

John Hilliard can be reached at