Oil refinery workers in the United States have walked out in their first national strike in 35 years.
About 5,500 workers at 11 plants are taking part.
Picket lines have been set up outside refineries in California, Kentucky, Texas, Washington, Indiana and Ohio.
The plants account for 13 percent of US refining capacity.
The strike has hit big oil firms Shell, BP, Marathon Petroleum and Lyondell Basell.
The strike forced the 166,000 barrel-a-day Martinez plant in California to shut down completely.
The workers’ United Steelworkers union called the strike on 31 January after talks with bosses over contracts broke down.
The strike is about pay and safety.
The union wants to double the size of the annual pay increases, get more healthcare coverage and reduced use of non-union contract workers.
The walkout initially involved nine plants but the strike spread last weekend as workers in Indiana and Ohio downed tools.
A full walkout of refinery workers would disrupt 64 percent of US fuel output.
The last national strike by oil refinery workers was in 1980, when they struck for three months.