CARSON, Calif. and HOUSTON (KABC) -- Oil workers from coast to coast went on strike Sunday. They started to walk off the job around midnight when their union failed to reach a deal with the energy industry. It's not clear how many workers are on strike.



The contract in dispute covers about 30,000 workers at refineries, pipelines, oil terminals, and petrochemical plants across the country. A Tesoro spokeswoman confirmed work stoppages at the company's operations in California, Washington and North Dakota. In California, Tesoro refineries are located in Carson and Martinez. About 800 workers were affected in Carson.



"Our comprehensive contingency planning has prepared us to safely operate our facilities. We have successfully made the transition and are operating our Carson refinery despite the USW violating the longstanding practice of providing a minimum of 24 hours' strike notice," said Destin Singleton, a spokeswoman for Tesoro.



Other facilities on strike include LyondellBasell in Houston, Texas; Marathon Galveston Bay Refinery in Texas City, Texas; Marathon Houston Green Cogeneration facility, Texas City, Texas; Shell Deer Park Refinery, Deer Park, Texas; and Shell Deer Park Chemical Plant, Deer Park, Texas.



At the Lyondellbasell plant in southeast Houston, workers started to protest around 6 a.m. Last night, more than a dozen workers walked off the job shortly after midnight.



Shell is representing the energy industry in labor talks with the United Steelworkers Association. Shell hasn't commented on what caused talks to break down. The USW sent a message to its members calling the latest offer from oil companies "insulting."



In a statement, USA International President Leo W. Gerard said, "Shell refused to provide us with a counter-offer and left the bargaining table. We had no choice but to give notice of a work stoppage."



USW International Vice President Gary Beevers, who heads the union's National Oil Bargaining Program, said in the same statement, "This work stoppage is about onerous overtime; unsafe staffing levels; dangerous conditions the industry continues to ignore; the daily occurrences of fires, emissions, leaks and explosions that threaten local communities without the industry doing much about it; the industry's refusal to make opportunities for workers in the trade crafts; the flagrant contracting out that impacts health and safety on the job; and the erosion of our workplace, where qualified and experienced union workers are replaced by contractors when they leave or retire."



KTRK-TV contributed to this report.



