A Massachusetts specialty chemicals manufacturer has been pegged a severe violator of health and safety rules and is facing $129,200 in proposed fines by federal health and safety regulators after four employees were injured by an explosion in January.

The U.S. Occupational Safety and Health Administration cited North Andover, Massachusetts-based Rohm-Haas Electronic Materials L.L.C., a division of Dow Chemical Co., for eight serious, two repeat and one other than serious violations, the agency said Tuesday in a statement.

The explosion occurred while the employees were engaged in the trimethyl aluminum cylinder reclamation process, which involves purging the cylinders of residual amounts of trimethyl aluminum, according to the agency. An OSHA investigation found that Rohm-Haas failed to adequately design, inspect, maintain and operate the process to prevent oxygen from making contacting with and igniting trimethyl aluminum.

The plant lacked adequate precautions to prevent the ignition of flammable vapors during the process, did not protect the reclamation system against the probability of fire and explosion and stored flammable liquids improperly, among other violations, according to the statement.

Rohm-Haas also failed to fully assess the workplace to determine hazards and appropriate personal protective equipment for employees and did not provide and require the use of all necessary personal protective equipment — hazards the company was previously cited for by the agency in 2014.

The company was placed in OSHA’s Severe Violator Enforcement Program, which focuses resources on inspecting employers who, according to the agency, have demonstrated indifference to their Occupational Safety and Health Act obligations through willful, repeated or failure-to-abate violations.

“Plant employees were needlessly exposed to fire and explosion hazards due to the deficiencies in the trimethyl aluminum reclamation process and other inadequate safeguards,” Anthony Covello, OSHA’s area director for Massachusetts’ Middlesex and Essex counties, said in the statement. “While Rohm-Haas has indicated that it is no longer manufacturing or reclaiming such pyrophoric materials, this explosion and the injuries that resulted could and should have been prevented.”

A company spokesperson could not be immediately reached for comment, but Rohm-Haas has filed a notice to contest the citations and penalties to the independent Occupational Safety and Health Review Commission, according to OSHA.