In the wake of a particularly deadly year at the nation’s oil refineries, United Steelworkers (USW) union members are using shareholder resolutions to call on major oil companies to improve disclosures on safety at oil refineries.

The resolutions, which were filed by the AFL-CIO Reserve Fund, call on the board of directors at Marathon Oil, Valero, Tesoro, and ConocoPhillips to disclose the board’s oversight of process safety management, staffing levels, and the inspection and maintenance of refineries and other equipment. A similar proposal was also filed at Sunoco (NYSE: SUN), but was withdrawn when company officials agreed to comply with the request.

The Steelworkers say that increasing transparency in the industry is an important step in improving refinery safety.

“If these companies had to tell their shareholders and the public how they were staffing their refineries, how much overtime people were working, and how long units were going without basic inspection and maintenance, we know that they’d try harder to fix the problems,” said USW International Vice President Gary Beevers, who heads the union’s National Oil Bargaining Program. “We hope that by demanding this information we can force the industry to fix these problems before any more of our members die or are severely injured.”

The oil sector had a high fatality rate in 2010. In the months of April and May alone there were 13 fires, 19 deaths and 25 serious injuries in the oil industry, according to the USW. One of the most deadly accidents was the April 2 explosion at a Tesoro refinery in Anacortes, Wash., that killed seven workers. A heat exchanger blew apart along cracks in welded areas. Washington State Department of Labor & Industries (L&I) inspectors determined the company failed to correctly test the equipment for cracks.

L&I Director Judy Shurke told reporters at a press conference last year, “The bottom line is that this incident, this explosion and these deaths were preventable.” The agency imposed a record fine of $2.39 million. Tesoro is appealing it.

Mark Laurence, who works at the Tesoro refinery in Anacortes, presented the shareholder resolution at his company’s annual meeting in San Antonio, Texas, yesterday.

“Seven people died after the explosion at my refinery,” Laurence said. “We hope that by taking our message to shareholders we can force our company to take a more serious approach to safety and fix the hazards in our refinery before anyone else dies.”

The USW represents 850,000 workers in industries including metals, rubber, chemicals, paper, oil refining and the service sector.