In 1989, Cynthia Babich moved into a small but neat house near Torrance that had a backyard big enough to raise her chickens. But soon the chickens were laying eggs contaminated by the now-banned pesticide DDT.

At the same time, Babich’s neighbors up and down West 204th Street were complaining of a host of health problems ranging from rashes, headaches, nosebleeds and achy joints to cancer.

After four years of health complaints by Babich and her neighbors, the Environmental Protection Agency discovered chunks of DDT the size of bowling balls in her backyard and on her neighbors’ lawns. The EPA concluded that the DDT, a pesticide banned in 1972 because it was linked to cancer and reproductive problems, came from the Montrose Chemical Corp. factory up the road, which had closed in 1982. Montrose denied any connection.

Also in the area was a World War II-era synthetic rubber plant where old waste pits known to contain benzene were located. Benzene is linked to cancer.

Babich and her neighbors were relocated from their quiet street after the old DDT factory was named a federal Superfund site. And after years of negotiation, Shell Oil Co. and Dow Chemical Co., which operated the former synthetic rubber plant, bought 65 of the homes in the area and razed them last year. With the DDT removed and waste pits capped, Shell is planning to build a park in the area soon.

Babich and her neighbors were lucky they found a solution to their toxic nightmare. But many residents of Los Angeles are not so fortunate.

Los Angeles is a toxic grab bag of chemicals. Thousands are stuck living next to concrete plants, metal-plating businesses, hazardous waste transfer stations, landfills, and former oil refineries they feel threaten their health every day.

They say they are exposed to chemicals that cause everything from asthma and cancer to diabetes and birth defects. But government officials say it is difficult to link toxic sites to health problems.

“Often, the health effects are manifested 10 to 20 years later, and it is hard to determine what caused them,” said Dr. Paul Simon, director of the county’s health assessment and epidemiology department. “There is certainly a lot of community concern, and the health department is trying to be proactive to prevent any problems from occurring.”

The state won’t concede there is a direct link between toxic sites and health problems, either. “I’ve been here 10 years and I’ve yet to work on a site where the health effects were actually proven,” said Ron Baker, a spokesman for the state Department of Toxic Substances Control.

But those who investigate toxic sites and their effect on nearby residents disagree.

Bahran Fazeli, staff scientist for Communities for a Better Environment, a nonprofit organization in Huntington Park, said he has seen residents living at the William Mead Housing Project in Lincoln Heights develop cancer because the housing project sits on top of a former oil refinery.

“There is a high level of lead in the soil, which leads to developmental disability in children, and high levels of polyaeromatic hydrocarbons, which is a carcinogen,” Fazeli said. “The case of contamination is very serious.”

Residents have also been complaining of sore throats and watery eyes. The L.A. Housing Authority is spending $1.5 million to clean up the toxic contamination at the housing project, where 1,400 residents, most of whom are Latino or Asian, live.

A major toxic risk in Los Angeles comes from heavy metals left in the soil. Airborne materials from factories and refineries create another hazard. Sulfur dioxide from power plants and refineries are said to lead to increased lung disease and breathing problems for asthmatics.

In Huntington Park near Vernon is an area known as Asthmatown, where the residents live next to several heavy industries. “You have recycling facilities, huge paper facilities, heavy metal-plating facilities,” Fazeli said. “The majority of the children (in the area) have asthma.”

These days, one of the most notorious contaminated sites in Los Angeles is the Belmont Learning Complex, where the L.A. school district wanted to build a new high school. But the school project site is a former oilfield that contains explosive methane gas and toxic hydrogen sulfide. The school board voted in January to abandon the project due to concern that it would endanger students’ and teachers’ health.

Other inner-city schools have confronted similar toxic problems. A few years ago, the opening of the Jefferson Middle School in South Los Angeles was delayed because of concerns about underground contamination, after it was revealed that the campus was located across the street from a former chrome-plating plant. Subsequent tests of the water table showed high levels of hexavalent chromium and the solvent trichloroethylene, both of which have been linked to chronic health problems.