WILMINGTON — As children played in the schoolyard at Hawaiian Avenue Elementary last week, three somber-faced safety inspectors wandered from one classroom bungalow to the next, poking a long metal rod into vents at the bases of the one-story structures.
They also drilled holes in the schoolyard blacktop, through three feet of dirt, using the probing rod to suck air from the underlying soil. The workers studied the needle on a hand-held meter. It didn't budge.
"That's the way we like to find these places: empty," said Carroll Dailey, assistant director of facilities in the harbor area for the Los Angeles Unified School District. "But it's very important that we check and see."
The ritual at Hawaiian Avenue is being repeated at many schools throughout the Los Angeles area as inspectors probe below school buildings and playgrounds for accumulations of methane gas--any buildup that could lead to an explosion like the one March 24 in the Fairfax business district on the Westside.
So far, no dangerous amounts of the gas have been discovered at any of the three schools tested during the first two weeks of the district's regionwide inspections. The schools tested, all in the harbor area, are Hawaiian Avenue in Wilmington and Towne Avenue and Leapwood Avenue in Carson.
During the next several months, the district plans to check 180 of its 818 schools for methane seepage. The schools are located near current and former oil fields, drilling sites and landfills. Schools in the harbor area, where nearly 40 will be tested, rank among the most susceptible to methane seepage of those targeted by the district, officials say, because of the region's concentration of oil deposits and former landfills.
Methane is a principal ingredient of natural gas and a byproduct of decomposing trash. It is colorless and odorless, although in some cases methane seepage has been detected by a strong smell that comes from other gases emitted by decomposing trash.
If methane accumulates in an enclosed area and constitutes more than 5% of air volume, exposure to any source of ignition--indeed, just turning on a light--could result in an explosion or a fire.
"We started with the harbor area because there are a larger number of schools sitting near landfills or next to or on top of oil deposits," said Jack Waldron, supervisor of safety programs for the school district. "We want to make sure we do not have the same kind of incident that happened at the Ross clothing store."
The explosion and fire in the Fairfax business district, which began in the basement of a Ross Dress for Less store, injured 22 people and demolished the shop. Fire officials have said the blast occurred after a spark ignited methane that was seeping from an old oil and natural gas field 50 feet below the earth's surface.
School safety officials became involved in the Fairfax incident because of methane seepage at nearby Hancock Park Elementary School, which had to be closed for three days to vent the gas. Officials say they have been monitoring that campus daily since the March explosion, but have found gas only underneath the playground, and in such small quantities that it is not hazardous.
School safety officials did not learn until after the Fairfax incident that oil deposits and drilling sites could cause excessive methane seepage, they say. Previously, methane seepage was linked mostly to landfills.
"We want to screen these schools so we know what's going on," said safety officer Bill Piazza. "It's like medically screening a person for cancer. We're medically screening the schools for methane."
School safety officials say methane explosions are rare and there appears to be no imminent danger at any of the school sites they are surveying. Waldron, the safety programs supervisor, said people living near potential sources of methane seepage will be notified if the district finds a problem at a school in their area.
"Most people don't check their homes, but this is not something they should lose sleep over," Waldron said. "If we find a problem, we'll let people know . . . (but), personally, if I was aware that I was living next to a former landfill or an oil deposit or former drilling site, I would check it out."
District officials several years ago initiated methane testing at two schools in the San Fernando Valley that are adjacent to landfill sites and where methane had been detected. Measures have been taken at both schools, Francis Polytechnic High School and Arminta Street Elementary, to relieve methane accumulation, and monitoring continues, officials say.
If methane is discovered at potentially dangerous levels during the district's regionwide inspections, schools will be evacuated until the gas is adequately vented or a collection system that would burn off the gas is installed, Waldron said.