WASHINGTON (AP) _ The Labor Department on Tuesday announced plans to fine Chevron U.S.A. Inc. $877,000 for 114 safety violations in connection with a Richmond, Calif., refinery fire last spring in which three workers were severely burned.

''The great tragedy of these injuries is that they were avoidable,'' Labor Secretary Elizabeth Dole said in announcing the findings of the department's Occupational Safety and Health Administration, which inspected the refinery after the accident.

OSHA concluded that Chevron was aware that workers responsible for aiding firefighters should have had protective equipment and clothing. It said individual refinery workers and union officials have been requesting protective equipment for several years but the company saw no need for it.

''The company failed to provide even this most fundamental basic equipment,'' Mrs. Dole said.

Chevron spokesman Jeff Krag said the company would contest the fines.

The company has 15 days to contest the fines in administrative proceedings before the department makes them final.

The safety agency determined that the April 10 fire began when a pipe carrying highly pressurized hydrogen gas separated at a weld. The resulting fire and explosion weakened an adjacent reactor, which fell and engulfed four workers in flames.

Three who were wearing no fire-resistant clothing received second- and third-degree burns over as much as 70 percent of their bodies from hot oil.

The fourth worker, a firefighter, escaped with minor first- and second- degree burns on his face because he wore fire-resistant clothing that covered the rest of his body, the department said.

Five other workers suffered less serious injuries.