RICHMOND, Calif. — A major fire at one of the country’s biggest oil refineries that sent hundreds of people to hospitals with complaints of breathing problems will push gas prices above $4 a gallon on the West Coast, analysts said Tuesday.

The fire, which sent plumes of black smoke over the San Francisco Bay area, erupted Monday evening in the massive Chevron refinery. It was out early Tuesday.

The West Coast is particularly vulnerable to spikes in gasoline prices because it’s not well-connected to the refineries along the Gulf Coast, where most of the country’s refining capacity is located, analysts say.

The Chevron refinery is particularly big and important to the West Coast market, said Tom Kloza, chief oil analyst at Oil Price Information Service.

It produces about 150,000 barrels of gasoline a day — 16 percent of the region’s daily gasoline consumption of 963,000 barrels, he said.