Oct. 23 (Bloomberg) -- Caribbean Petroleum Corp.’s refinery and tank farm at Bayamon, Puerto Rico, is on fire after two explosions at the site today.

Firefighters are still fighting the blaze, the cause of which is still unknown, according to a spokeswoman for the local Guaynabo police force, who was speaking by telephone and asked to not be identified by name. She said the explosions happened at about 12:30 a.m. local time.

At least 11 tanks at the oil distribution center were ablaze, and firefighters were trying to prevent further explosions at 22 other tanks, local news service Noti Uno reported, citing police superintendent Jose Fugeroa Sancha.

CPC markets the Gulf brand on the island. The Bayamon facility, near the capital city of San Juan, can process 48,000 barrels of crude oil a day, according to the company Web site.

The sour-crude refinery isn’t operating, according to undated information on the Web site. The facility also houses a tank farm and oil-product import terminal.

Diesel, gasoline, No. 6 heavy fuel oil and jet fuel are all stored at the tank farm, Ricardo Castrodad, a spokesman for the U.S. Coast Guard, said in a telephone interview. Puerto Rican authorities have requested assistance from hazardous materials specialists in the U.S., he said.

Vessels must receive special approval to travel in a mile- long safety zone established by set up by local authorities from the Punta Catano to the Puerto Nuevo Intership facility, according to Castrodad.

There is a temporary flight restriction up to 15,000 feet and about a mile wide over the fire, Kathleen Bergen, a spokeswoman for the Federal Aviation Administration in Atlanta, said in a telephone interview. “That’s not unusual in this type of disaster,” she said.

More than 300 people have been evacuated from nearby homes, Ana Santos, a spokeswoman for the state emergency management agency. More than a hundred people are working to extinguish the fire she said.

Calls to the company seeking comment went unanswered.

To contact the reporter on this story: Gianluca Baratti in Madrid at gbaratti@bloomberg.netAaron Clark in New York at aclark27@bloomberg.net

Last Updated: October 23, 2009 10:18 EDT