The state Department of Health Services and the federal Environmental Protection Agency are agreed that the BKK landfill "may" be a threat to public health, because toxic chemicals do escape into the air and could invade ground water.
And they define the "population at risk" from the dump as the 30,000 to 40,000 people who live within a mile of it.
But as Ronald Gastelum, general counsel for BKK Corp., points out, there is a vast difference between saying the dump "may" be a danger and saying it "is" a danger.
No Final Answers
And West Covina city officials say that when they try to obtain a definitive answer from regulatory agencies to the question of whether it is safe to live next to the dump, they get equivocations and uncertainties, leaving them to draw their own conclusions.
Not surprisingly, the conclusions differ.
West Covina Mayor Chester Shearer, whose home is three-quarters of a mile from the dump, said he does not regard living near BKK as a serious health risk, although he believes it is prudent to be watchful about any hazards that might develop.
"There's nothing that causes me to be concerned," Shearer said. "I live closer than most, have raised three children and I'm not concerned."
However, Louis Gilbert, who serves on the city's commission on the dump and lives a mile and a half away, takes a different view.
"We have a veritable ocean of toxic waste, and no one can convince me it's not a health hazard to live next to it," he said.
Alan Kunihiro, who was one of the people evacuated after potentially explosive gas leaked out of the BKK landfill two years ago, said that he and many of his neighbors worry about the health risk and would move if they could.
Some are locked into their homes financially, he said, and some also feel uncomfortable about passing on a problem to someone else.
Ethical and Legal Worries
"The feeling I have is that I couldn't sell the house with any peace of mind," said Kunihiro, a 38-year-old computer operations supervisor.
He said his concerns are both ethical and legal, noting that he might incur liability if he sold the house to an unsuspecting buyer.
Health officials say that there are three principal ways that toxic substances from the dump can reach people.
One is through gases created by decomposition of waste. The gases can rise through soil to the surface, drift off the property and be inhaled.
Another is through contamination of the underground water supply by leachate, which is defined as any liquid that has passed through waste.
And the third is runoff of rain water from the dump onto neighboring property.
It is not clear how much toxic waste is buried at the dump because detailed records were not kept before 1978.
But the company estimates that since 1975, when hazardous waste began arriving in large volumes because other dumps had closed and disposal regulations had been tightened, BKK has taken in 3.4 million tons of such substances, ranging from a spoiled batch of vodka to acid solutions strong enough to burn the skin on contact.
The dump has received just about everything short of radioactive material.
More than 2 million tons of hazardous waste arrived at the dump in liquid form and was buried in drums, injected into wells or mixed with ordinary household trash and covered with dirt. Health officials are most concerned about those chemicals in the waste that are known to cause cancer.
Little Cancer Risk
However, Lynn Goldman, an epidemiologist with the state Department of Health Services, said that the evidence so far suggests that there is little, if any, cancer risk to residents.
Researchers at the USC Department of Preventive Medicine cancer surveillance program reported a year ago that cancer rates of children and adults living near BKK are, "if anything, slightly lower than average." The lower incidence could be explained by chance, they said.
Goldman said the findings were not surprising--or conclusive--given the fact that it may take years, even a decade or two, for cancer to develop after exposure.
Residents criticized the USC study because it failed to include older neighborhoods north of the dump. The USC research team is looking at those neighborhoods now and will issue a report this fall.
Goldman said that the cancer study was undertaken because residents, in talking to each other, were startled by the number of cancer cases in their own families.
But because the chance of developing cancer in one's lifetime is one in four, Goldman said, it is not surprising to find many histories of cancer in any neighborhood.
Experts hired by BKK attorneys as part of its defense against lawsuits brought by residents contend that the cancer risk, if any, is slight.
A joint declaration by department chairmen in schools of public health and medicine at Harvard, New York University and the University of California, Irvine, says that there is no reason to believe that residents will suffer any toxic or carcinogenic effects from breathing air near the dump.