(Adds comment from Shell)
By Erwin Seba
HOUSTON, March 12 (Reuters) - The United Steelworkers unionand oil companies have reached a tentative deal to end thelargest U.S. refinery strike in 35 years, the labor group andpeople familiar with the negotiations said on Thursday.
The new agreement for about 30,000 workers would last fouryears, a year longer than previous agreements. The deal, whichstill needs to be ratified, may not end strikes right away atall refineries that have suffered walkouts as local unionchapters could still need to work out pending issues.
"We salute the solidarity exhibited by our membership," saidUSW International President Leo Gerard. "There was no way wewould have won vast improvements in safety and staffing withoutit."
Lead industry negotiator Royal Dutch Shell Plc saidunion members are set to vote on the agreement in coming days.
Tesoro Corp told employees in a letter seen byReuters it was "supportive of the agreement" and would try toquickly settle local issues "to enable our employees return towork."
The tentative contract contains language that addressesworker fatigue, which is tied to accidents, and the use ofcontractors versus unionized labor. It also safeguards gainsmade in previous contracts, the union and sources said.
They added that annual wage increases would be 2.5 percentin the first year, 3 percent each in years two and three, and3.5 percent in the fourth year.
Twelve refineries with a fifth of U.S. refining capacityhave been hit by strikes over the past 40 days. Companies haveresponded by calling in temporary workers after 6,550 peoplewalked off the job.
Only one plant, Tesoro's 166,000-barrel-per-day (bpd)refinery in Martinez, California, was shut by the strike as itwas already undergoing maintenance when the walkout started. Thecompany said it will reopen when the strike ends.
The contract would cover refineries owned by Exxon MobilCorp, BP Plc, Valero Energy Corp andChevron Corp among others.
On Wednesday, in a message to its members, the union said itwas assembling its policy committee, which represents the rankand file, to review proposals from industry during contracttalks.
That move was widely seen as a signal that the strike may benearing an end as the union pushed for higher wages and what itcalled better safety practices in a new pact for about 60plants. (Editing by Terry Wade, Lisa Shumaker, Bernard Orr and AlanRaybould)