By Erwin Seba

HOUSTON, (Reuters) – Exxon Mobil On Thursday, Corp (NYSE: ) sent out a message to thousands of union workers at the Beaumont, Texas refinery, stating that non-union jobs have better pay.

We cannot make promises and will not. Exxon stated in a message titled a “decertification upgrade” that it can confirm that employees who are not represented at similar sites receive 5%-7% more salary and offer the same benefits.

This message is sent two weeks ahead of the vote by the 585 workers who are locked out to remove the United Steelworkers union (USW) Local 13-243 (369,000 barrels per-day) from the adjacent lubricant oil facility.

A representative of the United Steelworkers Union 13-243 did not immediately comment on the message.

Workers will vote via mail from Nov. 12 to Dec. 22, in a decertification process overseen by U.S. National Labor Relations Board. If successful, it will be removed by the USW.

Exxon has set out two conditions in order to close the lockout. They are either adoption of the contract it proposes, or decertification USW13-243.

In a secret ballot vote, a majority of union members voted against the contract proposal on October 19.

Exxon froze the workers May 1, after four months of negotiations failed to reach a deal that would have eliminated job seniority. This gives workers a voice over their job assignments and ensures the best workers are operating refinery units.

Exxon stated that job security and changes must be eliminated in order to make the refinery competitive even in low-margin areas.

Exxon maintains the refinery’s capacity at 60% with both managers and supervisors, as well as temporaries.