The U.S. Chemical Safety Board said a malfunctioning fuel monitoring system was the likely cause of the explosion and massive fire at a Puerto Rican fuel storage depot last month, reported by Reuters. No one was killed at the Caribbean Petroleum Corp. facility in Bayamon, near the Caribbean island''s capital, San Juan. But hundreds of people were evacuated as firefighters battled for three days to contain the blaze, which grew to engulf more than half of the fuel depot''s 40 tanks. The blast damaged homes and businesses more than a mile from the facility and officials are still working to ascertain the environmental damage it caused. The blast resulted from the accidental overfilling of a tank with gasoline from a ship docked in San Juan harbor that occurred because of a faulty monitoring system, CSB officials said. Employees were unaware of the overfilling because the facility''s computerized level monitoring system was not fully operational. As the gasoline spilled undetected from the tank, it vaporized and spread across the facility, creating a 2,000-foot wide vapor cloud that ignited once it contacted an ignition source.