The DuPont company will pay a $724,000 fine to settle violations related to a 2010 explosion that killed one person and injured another at its River Road chemical plant in the Town of Tonawanda, the Environmental Protection Agency announced Thursday afternoon.

The Nov. 9, 2010, chemical explosion and fire occurred at the DuPont Yerkes plant when flammable vinyl fluoride got inside a process tank and exploded, the EPA said.

An investigation revealed “several areas of the facility’s operations … had been in violation of the Clean Air Act,” according to the EPA.

A contract welder at the DuPont plant died, and another worker was badly burned.

The U.S. Chemical Safety Board concluded that hazards had been overlooked by DuPont, which the EPA’s investigation confirmed, the EPA said.

Vinyl fluoride is used to make plastic products.

Richard J. Folaron, 57, of South Wales, died instantly and William R. Freeburg of Angola was injured in the plant on River Road near Sheridan Drive. They were working on a 10,800-gallon storage tank used to hold slurry involved in the production of photovoltaic panels; the tank in question had been emptied weeks before.

Flammable vinyl fluoride vapor flowed, undetected, into the tank from interconnected tanks that were in service. The vapor ignited while Folaron was welding on top of the tank.

In its release Thursday, the EPA said the violations had been addressed by DuPont prior to the settlement.

DuPont installed equipment and developed more-stringent safety procedures to reduce the risk of a similar explosion, according to the agency’s release.

“Safe and reliable operations are our top priorities, and we have implemented extensive modifications to the process and operating procedures at the site,” Warren Hoy, the DuPont Yerkes plant manager, said in a statement.

Hoy said the company has already acted on recommendations from the investigations conducted by the U.S. Chemical Safety and Hazard Investigation Board, the Occupational Safety and Health Administration and its own internal investigation.

DuPont worked with the EPA, corrected problems and completed several chemical safety-related improvements at the facility, the agency said.

Among the improvements, DuPont:

• Upgraded its process to analyze potential vinyl fluoride hazards;

• Took actions to reduce the risks relating to vinyl fluoride vapors;

• Changed the configuration of the equipment to reduce the chance of dangerous gas build-up;

• Installed new controls and additional protective equipment;

• Improved vinyl fluoride monitoring;

• Improved processes and operating procedures at all of its facilities to avoid a similar vinyl fluoride incident.

“EPA’s investigation of DuPont highlights the importance of preventing, preparing for and responding quickly to chemical releases and other incidents,” Judith A. Enck, EPA’s regional administrator, said in a release. “It is imperative that DuPont and other businesses make protecting human health and the environment their top priority. The chemical explosion that happened at DuPont in Tonawanda must never happen again.”

The EPA reported that the company has invested in nearly $7 million worth of safety-related improvements since the incident.

Besides the fine, DuPont must spend $112,000 to buy vapor and radiation detection equipment for a local volunteer fire department and pay for training, the EPA said.

The Brighton Fire Department will receive first-responder equipment and training for the detection of radio isotopes and chemical gases, Hoy said.

The Clean Air Coalition, a Town of Tonawanda organization that focuses on environmental issues in the industrial River Road corridor, lauded EPA officials for the DuPont settlement and fine.

“We are hopeful that this action will improve operations at the facility, and reduce the health and safety risk that vinyl fluoride vapors pose to workers and residents that live near the plant,” said Rebecca Newberry, the organization’s director.

Germain Harnden, director of the Western New York Council on Occupational Safety and Health, added: “Simply put, this is about protecting the health and well-being of Western New Yorkers. This tragedy brings to light the real dangers of working as a contract worker and not being properly protected on the job site.”