[NEW YORK] Union workers at nine US oil refineries were striking on Monday for a second day after contract negotiations with plant owners broke down.
But only one of the nine plants had curtailed production as a result of the strike, Bloomberg News reported.
The United Steelworkers Union announced the stoppage began 12.01 February 1 at refineries in California, Kentucky, Texas and Washington state. The plants are owned by Shell, LyondellBasell, Marathon Petroleum and Tesoro.
The USW took the action after negotiations broke down with Shell, which is leading the talks on behalf of refiners.
A USW statement blamed oil company intransigence and listed a series of problems, including "onerous overtime," "unsafe staffing levels" and the "erosion of our workplace" due to outsourcing of work to contractors.
The nine refineries account for about 10 per cent of US refining capacity, according to Bloomberg.
However, the strike could potentially spread to a much larger group of plants.
The USW said it represents 65 refineries accounting for nearly two-thirds of total US output. The other refineries, including those of ExxonMobil and Chevron, are currently running under a rolling 24 hour labour contract extension, according to the union.
The labor tensions cause a 7 per cent jump in gasoline futures prices since Friday amid concerns supplies of refined products could be constrained.
Tesoro said it had shut its Martinez, California refinery in light of the strike, viewing a full closure as the safest option given maintenance that had already been going on.
Tesoro will keep production up at its Anacortes, Washington and Carson, California plants.
"We intend to safely operate our refineries with fully qualified personnel and are confident in our ability to continue to responsibly produce transportation fuels to meet the needs of our customers," said Keith Casey, executive vice-president of operations for Tesoro.