Potentially explosive levels of gasoline-type hydrocarbon vapors have been discovered at 12 sites in the El Porto area of Manhattan Beach along The Strand, Los Angeles County Health Services officials have disclosed.
Health officials told The Times of the discovery Tuesday, just hours before a public hearing in neighboring El Segundo. The hearing was called to update residents on a recent discovery that hydrocarbon vapors from waste pools at the Chevron USA Inc. refinery in El Segundo have spread beyond the refinery's northern boundary into the city's manufacturing district.
While Chevron and El Segundo city officials maintain that only extremely low levels of the potentially flammable, toxic vapors have been found in El Segundo, county officials reported that levels discovered in El Porto reach at least 10,000 parts per million, the level at which hydrocarbons become explosive.
The vapors were discovered in shallow wells dug by Chevron after its discovery of the El Segundo vapor migration last month. The wells are part of a study launched by the refinery to determine the extent of the vapor problem. El Porto lies along the refinery's (and El Segundo's) southwestern boundary.
Jose Ochoa, industrial hygienist with the county's hazardous materials section, said the discovery was made last Friday by Chevron and reported to the county Department of Harbors and Beaches and subsequently the state Department of Health Services. The area involved is a narrow strip along The Strand that runs from 40th Street to Manhattan Beach's northwestern boundary.
Meanwhile, regional water quality officials have said they plan to require all Southern California oil refineries to begin drilling and testing for underground petroleum pools. Nine of the region's 10 refineries are in the South Bay-Harbor area.
Threat of Explosion
Chevron's El Porto discovery has raised a state health official's concern about the danger of fire and explosion.
Rick Notini, waste management specialist for the state, said, "Our main concern is the short-term threat of explosion, especially since there are homes located within a couple of blocks of these readings."
Notini said that field instruments registered levels as high as 10,000 parts per million, but added that because the instruments only go that high, "we can probably assume that it's higher. We just don't know how much higher.
"It is becoming obvious that the problem extends beyond El Segundo, and we don't know how far. It is already beyond last week's assumption and seems to be moving in two directions. I think we seriously need to look at the whole perimeter of that refinery and beyond. In fact, we'll probably require that."
Local officials, however, said it is too soon to ascertain whether there is an immediate hazard.
"We're not sure what the discovery means,' Ochoa said. "We don't believe there is an immediate safety threat at this point, but we will be monitoring the situation very closely."
Manhattan Beach Assistant Fire Chief Keith Hackamack said that the levels represent "the low end of flammability," adding that there is not yet enough information "to know whether we have a truly flammable mixture yet."
While Chevron officials were surprised to learn that the information had been made public, they confirmed that "unacceptably high readings" were discovered at the El Porto site and said they had planned to disclose the discovery in a press conference today.
"We did find unacceptably high levels in El Porto," Chevron spokeswoman Brenda K. Smyth said Wednesday, "and we're trying to understand those numbers now. This is a development we hadn't counted on, but we have notified the regulatory agencies and key city officials."
Smyth said Chevron will be conducting additional tests to determine the extent and cause of the unusually high readings.
Notini said that the state will probably require that Chevron conduct tests similar to those in El Segundo, where the company's independent consulting firm has been testing for buildup of hydrocarbon fumes at 48 structures in and around the initial discovery site.
The results of those tests were disclosed at Tuesday's public hearing, where Chevron officials said that in testing sewer and utility lines and cracks in the foundation where fumes could seep in, "there is no indication that vapors have entered any of the buildings."
Under a work plan unanimously accepted by El Segundo council members Tuesday night, Chevron officials will continue structure testing over the next six weeks in various homes, businesses and schools in the area.
The work plan--which also has received approval from all but one regulatory agency--will also include:
- Drilling of water wells to determine the extent of the liquid pool.
- Drilling of gas wells at 10-, 20- and 30-foot levels to determine the extent of vapor migration.
- Installation of permanent air monitoring stations to determine the quality of above-ground air.