The fallout from last year’s fatal San Bruno natural gas transmission pipeline rupture has spilled into Southern California where two 40-year-old butane storage tanks operated by a unit of a Houston-based company are stirring up local safety concerns. Three different risk scenarios completed in the past two years have stimulated debate.

Local residents have dug up historic records regarding the original siting criteria and the sites’ proximity to the active Palos Verdes earthquake fault in an area that they contend is known for having naturally occurring methane gas deposits and unstable ground.

Residents have hired a consultant and attorney, pressing for what they consider a more up-to-date and complete risk assessment along with court action to determine if the tanks should be removed. A Houston-based spokesperson for Rancho LPG Holdings has stressed that the company has held regular meetings with the community and told them about recent risk assessments that were completed.

A report in Monday’s Los Angeles Times cites residents in the port community of San Pedro as being concerned about the circular steel storage structures containing up to 25 million gallons of butane in the wake of the September 2010 San Bruno incident that resulted in an explosion and fire that killed eight people and devastated a residential neighborhood 10 miles south of San Francisco.

The Times report called the latest concerns “an emotional debate” that has raised various horrific scenarios involving fire, explosions and terrorist attacks at the 20-acre facility owned by Rancho LPG, a unit of Plains All American Pipeline in Houston. The company stands behind the operations and maintenance of the twin 80-foot tall tanks that have operated safely for four decades.

State, federal and Los Angeles City Fire Department records indicate that the site meets all regulatory requirements, and the facility’s fire fighting system was recently inspected and recertified, according to the Times.

Local residents have tried to get either the Los Angeles city attorney or the state attorney general’s office to seek a court hearing to determine if the tanks are hazardous enough to mandate their removal. Both the city and state have turned down the requests, noting that the butane tanks have not caused any harm.

The debate publicly remains over competing risk analyses — one completed two years ago by Rancho LPG noting as a worst-case scenario a vapor cloud explosion that would impact a half-mile-radius around the tanks, which are located near a refinery, shopping center, business park and playing fields about a mile from the Los Angeles harbor.

Another scenario by a consulting firm hired by residents last year concluded the worst case would involve a 6.8-mile radius from the site, spreading over all of San Pedro and going into parts of neighboring Long Beach. A third assessment performed by a University of Southern California doctoral candidate looked at the consequences of a possible terrorist attack involving a rocket-propelled grenade and determining that the impact area would have a 2.9-mile radius.

A spokesperson for Rancho LPG was quoted in news report as saying the tank operators were doing everything possible “to reduce off-site consequences” from the facility. A call by NGI to the spokesperson was not immediately returned.

©Copyright 2011Intelligence Press Inc. All rights reserved. The preceding news reportmay not be republished or redistributed, in whole or in part, in anyform, without prior written consent of Intelligence Press, Inc.