SAN JUAN, Oct. 26 (UPI) -- Federal agencies are investigating whether the explosion and fire at a Puerto Rico storage facility Friday was an act of sabotage or an accident, officials say.
Graffiti found in two tunnels in San Juan referred to a fire, FBI agent Harry Rodriguez said. In both cases the graffiti said "Boom, fire, RIP, Gulf, Soul, ACNF." The company that runs the facility owns the Gulf Oil brand, but it is unknown what ACNF refers to, he said.
The explosion and resulting fire destroyed seventeen storage tanks. Agents from the FBI and the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives will try to determine whether the initial explosion was deliberate or accidental, CNN reported.
The explosion rattled the area with the force of a 2.9 magnitude earthquake, authorities said. The blaze was extinguished Sunday but some tanks continued to smolder and crews remained in place to guard against possible flare-ups.
An estimated 700 people were evacuated from the vicinity and spent the night in shelters Sunday night.
President Barack Obama has declared an emergency in Puerto Rico, which will make federal aid available.