It is a mystery that has long baffled local and California health investigators, and now the U.S. Environmental Protection Agency will take a look at why so many children are dying of cancer in the San Joaquin Valley farm town of McFarland.
In 1992, after more than five years of testing by local and state health agencies, a team of government and university scientists left McFarland frustrated by the same question: Were 13 childhood cancer cases over a seven-year period a statistical anomaly in the town of 6,200 or the byproduct of pesticide contamination in the environment?
Since then, seven more children in the poor, Latino town in Kern County have been diagnosed with cancer, and parents of these children, along with community activists, have demanded that the EPA come in to review the old research and conduct new studies.
This week, a team of EPA investigators is meeting with county health officials and residents as a first step toward a comprehensive study of the soil, air and water.
"We've looked at all the old data and while the county and state did a lot of good work, they didn't sample deep into the soil, they didn't sample for all the possible chemicals and they didn't test the air," said Keith Takata, an EPA official based in San Francisco.
"So we're going to do that and see if there's some way we can identify a cause."
Straddling California 99 in a sea of vineyards, orchards and cotton fields, McFarland calls itself "the heartbeat of agriculture." In the early 1980s, after five children in one neighborhood were diagnosed with cancer, residents pointed an accusatory finger at the pesticide-laden fields surrounding their homes.
In ensuing years, eight more cancer-stricken children throughout the town were added to the list. This was three to four times the expected rate. Half the children have died of the disease.
County and state investigators collected water samples from homes and drinking-water wells and tested for about 100 chemicals. They scraped soil samples from parks, playground and yards. They even measured radio frequency waves from a Voice of America transmitter at the edge of town. Nothing conclusive was turned up.
"We even widened the investigation to compare four counties in the San Joaquin Valley," said Dr. Babatunde Jinadu, director of public health for Kern County. "Nothing could be found to answer the question why so many children in McFarland had cancer."
Pinpointing a cause, he said, was especially difficult because the children had many different kinds of cancers -- liver, lymph node, blood, bone, eye, adrenal, kidney.
Since 1992, as each new childhood cancer has emerged, residents have continued to blame agricultural chemicals -- a spring, summer and fall assault that includes airplanes dusting defoliants on the cotton fields.
A group calling itself "Healing Our Mother Earth," headed by a former McFarland mother, petitioned the EPA last year under a provision of the Superfund law. The members alleged a number of gaps in the local and state investigation, including the lack of any detailed sampling of the air.
"This wasn't a classic Superfund case but we thought that the least we could do was reevaluate the old information," said the EPA's Takata. "Then the state came out with new statistics showing seven new childhood cancer cases."