LOS ANGELES (1/31/99) -- In the days before sophisticated monitoring equipment, coal miners discovered that canaries were sensitive to the odorless methane gas which often built up inside the mines. When the tiny yellow birds began to droop, miners knew their lives depended on quickly leaving the shafts before an accidental spark detonated an explosion.

In southeast Los Angeles, children are like the canaries carried into the coal pits of Pennsylvania and West Virginia. Like canaries, children are more sensitive to toxic chemicals than adults. An examination of the location of schools in southeast Los Angeles reveals that they play and study in a chemical soup blanketing whole communities. And the disastrous health effects of that pollution often show up first in the schoolyard.

In 1989, southeast LA's industrial past resurfaced in one of the three poorest cities in the US - Cudahy. At Park Avenue Elementary School, parents and teachers noticed a black tar-like substance bubbling up through cracks in the asphalt covering the school playground. It had an acrid, pungent smell.

The 1989 incident was not the first. A Cudahy policeman, Jose Mireles, told the LA Times that "it was coming up when I attended school there from 1971 to 1975. There was also a rotten egg smell in the summer. You couldn't breathe. We thought it was normal."

By 1989, people didn't think it was normal anymore. Children complained of getting bad headaches, or that they felt weak when they got home from school. Parents and teachers demanded answers about the possible consequences to children playing in the yard. The school district and the Environmental Protection Agency discovered the black sludge contained methylene chloride, methylnapthalene, phenanthrene, pyrene, benzo pyrine and hydrogen sulfide. These chemicals can cause cancer, eye and skin irritation, and kidney and respiratory illness.

The school had been built in 1968 on top of an old landfill, into which industrial wastes had been dumped in the 1930s, 40s and 50s. The district finally evacuated the school for a year. An asphalt cap with an undlying liner was put over the schoolyard, and the school reopened once more. Continuous monitoring afterwards found no detectable traces of toxic chemicals.

Past industrial contamination isn't the only source of toxic pollution, however. Many southeast schools are located next to existing sources of toxic emissions.

In 1986, a ruptured pipeline at a Purex plant released a cloud of chlorine gas which drifted over Tweedy Elementary School in Southgate. Seventy-one people were sent to the hospital, including 27 children.

The spill galvanized Tweedy's parents, who demanded health testing for the school's children and teachers. County Health Department officials denied that children would suffer longterm health effects from exposure to chlorine gas. But "if you have an asthmatic child sensitive to this environment, your child should not be here," said the department's Dr. Paul Papanek.

Parents discovered that the school was surrounded by at least 16 different industrial facilities. Some had been cited by the Air Quality Management District for a variety of violations, including open spray-painting, emitting dust and odors, and illegal emissions of industrial solvents.

But the most dangerous facility was located just on the other side of a chain link fence from the schoolyard. Cooper Drum Co., which cleans and stores industrial drums, for years had been emitting significant amounts of hexavalent chromium, a chemical identified as a carcinogen in the mid-1980s, and ammonium hydroxide.

Ten months after the spill, principal David Sanchez requested and received a transfer, since he continued to suffer respiratory problems, nausea and headaches. Parents protested that the district was transferring the principal, while leaving the children exposed to the same conditions.

Finally, Tweedy was closed, and moved a few blocks away. Today, the original Tweedy schoolyard is still vacant. Weeds grow up through the schoolyard, and abandoned buildings fall into disrepair. The drum facility is still in operation.

In 1988, concerns over the effects of hexavalent chromium led to protests at another southeast LA school - Suva Elementary and Intermediate School in Bell Gardens. That year two teachers miscarried deformed fetuses, while third teacher had to abort one. Research by Suva employee Roberta Swanson revealed that four out of five pregnant school employees had miscarried.

The Suva school sits right next to two chrome plating plants, Chrome Crankshaft Co. and J&S Chrome Plating Co. Both have been discharging hexavalent chromium for 30 years.

The Health Department's Dr. Paul Papanek spoke to Suva teachers and parents, assuring them that the chemical's level at the school was similar to that in the Los Angeles Basin as a whole - five to ten nanograms per cubic meter of air. He admitted, however, that a longterm exposure of one nanogram can result in 150 additional cancer cases per million people.

Ultimately, despite studies, no direct cause was found for the high incidence of miscarraiges among Suva teachers. The school remains open, and the plating plants continue to operate. "In my opinion, the Board of Education has done everything it can," said Montebello Unified School District President John Cook. "There is really not a lot more we can do."

That lack of answers doesn't satisfy many teachers and parents, but it does highlight the problem of schools in southeast LA. They can't simply relocate children and teachers out of a community overburdened with toxic pollution.

The communities of southeast Los Angeles suffer from toxic contamination at a rate significantly higher than the LA basin overall. Pollution is concentrated in eight cities where the percentage of Latino residents ranges from 75% in Vernon to 93% in Maywood.

It is an overwhelmingly immigrant population -- as high as 52% in Huntington Park, and 58% in Cudahy. And it is a poor population. Cudahy and Bell Gardens are two of the three poorest suburban communities in the country, and unemployment is double the national average -- over 10% in every city.

A study by researchers at Occidental College found that about 493,000 blacks, Latinos, Asians and Native Americans in LA County live within half a mile of a hazardous waste treatment or storage facility, compared to 107,000 white residents.

It's no surprise, therefore, that Park Avenue Elementary School is located in Cudahy, rather than, for instance, the upper middle-class communities of Sierra Madre, San Marino, Palos Verdes or Bel Air. The children exposed to high levels of hexavalent chromium and other toxic air emissions from surrounding factories are the predominantly poor and minority children of southeast Los Angeles.

They are the canaries, involuntary participants in a huge environmental experiment. Damage to their health has become an early-warning sign of danger to the health of their entire population of the Los Angeles basin.