* USW says Exxon has failed to offer key safety provision
* Talks for a new contract to continue till mid-June (Adds contract details)
HOUSTON, April 27 (Reuters) - Negotiations for a new contract covering hourly workers at Exxon Mobil Corp's refinery in Baton Rouge, Louisiana, has become a scrap over a proposal on worker safety, The United Steelworkers union (USW) said on F rid ay.
Exxon and the USW are negotiating a new three-year contract during a 75-day extension from the previous three-year pact covering workers at the 502,000 barrel per day (bpd) refinery, Exxon's second-largest and the third largest in the country.
The USW said Exxon has failed to offer a key safety provision of the national contract agreed to by oil companies and the USW in February, and which four of Exxon's refineries approved at that time.
"All Exxon Mobil management has to do is treat us equally, is give us the same (national agreement) as they have offered to Billings, Beaumont, Torrance and Chalmette (refineries)," said Kenneth Duke, president of the USW local union in Baton Rouge. "This is all the company has to do to bring us a contract that we can ratify."
An Exxon spokeswoman said the company was disappointed that workers did not have an opportunity to vote on its most recent contract offer at Baton Rouge.
"We are disappointed that the United Steelworkers rejected our most recent offer, including wage increases that match the industry pattern," said Exxon spokeswoman Stephanie Cargile.
USW spokeswoman Lynne Hancock said the Baton Rouge members did not vote on the contract proposal because it did not match the national contract.
Specifically, the union said Exxon has not offered to Baton Rouge workers the national contract proposal with a provision for a process safety representative that USW and the company would appoint at the refinery.
"We value employee participation in all of our site safety programs," Cargile said. "Unfortunately, USW leadership has withdrawn from our Joint Health and Safety Committee and OSHA's Voluntary Protection Program (VPP), which has demonstrated success at other sites."
The process safety representative is intended to focus on safety and reliability in the refinery production process as opposed to general safety.
Federal safety investigators have criticized so-called "slips-trips-and-falls" general safety programs as providing a false sense of security about safety at oil refineries when potentially catastrophic problems are developing with refining process equipment.
"If the ExxonMobil Baton Rouge had been a VPP site, OSHA would not have included it in its National Emphasis Program," Hancock said. "The problem with VPP is that OSHA cannot come in unannounced to find out what is really happening in the facility."
An OSHA national emphasis program inspection at the Baton Rouge refinery in 2011 cited the Baton Rouge refinery for 20 serious violations.
Between 2007 and 2011, OSHA undertook a national emphasis program of inspections of the nation's refineries in the wake of the 2005 blast at BP Plc's Texas City, Texas, refinery, which killed 15 workers.
While most U.S. refineries agreed to the national contract in February, the contracts at several refineries expire after the national agreement was reached.
The agreement between Exxon and USW at Baton Rouge expired on March 31, but there is 75-day contract extension in place to continue talks. The talks will continue until mid-June. (Reporting by Erwin Seba; editing by Gunna Dickson)