New Tests Find Higher Level of Toxic Gas at Belmont Site

New state-ordered tests at the environmentally plagued Belmont Learning Complex have found potentially deadly hydrogen sulfide gas at concentrations nearly three times greater than any previously measured there, The Times learned Wednesday.

The findings highlight the unpredictability of safety hazards at the high school being constructed over a former oil field near downtown and further complicate the debate over the fate of the $200-million project.

The upward trend could cause the state toxics department to conclude that tests continue for a longer period before it will certify any remediation plan for the site.

However, a member of the district’s environmental safety team said he did not consider the higher readings alarming.

“We have known from previous testing that these levels are highly variable,” said Angelo Bellomo, the team’s environmental consultant. “I don’t think this is surprising or unexpected.”

The Los Angeles Board of Education has appointed a commission of civic leaders to recommend whether to abandon Belmont or finish it with costly remediation to ensure the safety of students and faculty.

The commission is scheduled to issue its report Oct. 20.

But as the deliberations go on, the California Department of Toxic Substances Control has required the district to continue taking readings of oil-related contaminants including toxic hydrogen sulfide and explosive methane.

The district has agreed to obtain certification of the site’s safety by the toxics department before opening the school.

Construction on the project was begun in 1997, before the environmental hazards were adequately investigated. District officials estimate that $125 million has already been spent. The board must weigh that expense--and the potential risks to children--against the urgent need for new schools.

In July, the school board plunged the troubled project into new depths of confusion. The seven-member board, controlled by a new majority of “reform candidates,” unanimously voted to set up an investigatory commission on whether to suspend construction of the downtown building. The board also voted to scale back work on the project until the commission makes its recommendations, but not to stop it altogether.

Earlier this year, tests overseen by the department showed that methane is pervasive on the site and that hydrogen sulfide occurs in some areas at dangerous levels.

As a result of those findings, the department asked for two more rounds of sampling to determine whether the contaminants are changing over time.

The latest round of tests, now being studied by environmental engineers, showed steadily increasing concentrations of hydrogen sulfide under the baseball field.

In the first round, the well yielded samples of about 3,000 parts per million. A second sample in the spring had 13,000 parts per million. The latest test, taken several weeks ago, included two samples, one of 18,000 and the other 33,000 parts per million.

Hydrogen sulfide is considered dangerous at levels of as little as 100 parts per million.

Bellomo said that any mitigation system would have to take into account the variability of conditions on the site at 1st Street and Beaudry Avenue, west of downtown.

“We will be considering remedial actions which assume the levels of H2S [hydrogen sulfide] we find at several areas of the site could occur almost anywhere on the site,” he said.

Since the contaminants are coming from crude oil deep underground, they cannot be eliminated. The usual method of remediation is to place a plastic barrier under buildings, with a collection system to remove hazardous gases.

Bellomo said the protection might have to involve some form of barrier across the entire site.

Hydrogen sulfide, known for its distinctive odor of rotten eggs, is considered harmful to human health at very low concentrations. Inhalation at higher concentrations can result in coma and death within a few seconds.

Hydrogen sulfide blocks the ability of the blood to carry oxygen to the brain, heart and other vital organs. In addition, it poisons the body’s tissues.

The air samples that contained the gas were taken about 30 feet underground at several locations on the 35-acre site. In most of the tests, the readings were low.

But one spot on the middle of a baseball field has shown consistently rising readings since the testing began in the spring.

In estimating the danger at Belmont, engineers must ask how likely it is for the gas to find a path to the surface and how much it might dissipate in getting there.