Stacey and John Quartarone of Carlsbad, Calif., lost son Chase, 16, to non-Hodgkins lymphoma in December.
A dying wish was for his parents to find out what caused his cancer.
"He said, 'Please don't let anybody else get this,'" mom Stacey Quartarone said.
The Quartarones are doing their best to honor their son's wish. They've done their research and have discovered others in Carlsbad who said they have cancer or whose family members developed it.
But what started as a quest to determine Chase's cause of death led them to what they believe is a so-called cancer cluster around Kelly Elementary School, which their son had attended.
"There were at least 15 confirmed cases of cancer in the last 15 years," Stacey Quartarone said. "We're positive that at least eight teachers have had different types of cancer in the last 10 years."
The Quartarones and others who believe something environmental is behind what they describe as an abnormally high number of cancer cases in Carlsbad pushed the school district earlier this year to perform soil testing.
"They went ahead and did two tests, and they came back negative," she said. "But they didn't test the soil, just playground sand."
Quartarone said two private companies hired by the school district tested the sand in a playground at Kelly Elementary School and another site. No one, she said, has revealed where the other site is or exactly what was tested.
The school district has yet to approve additional soil testing, she said.
"It's an issue of funding, and they feel the previous tests proved that everything is fine," she said.
But, she added, the district said it would take up the issue again if community members agreed to pay for the soil testing.
Carlsbad School District board of education president Mark Tanner said the city's schools are safe.
"The Board believes we have carefully and thoroughly evaluated the facts surrounding the safety of our schools," he said. "Multiple independent data indicate they are very safe environments wherein Carlsbad Unified students are educated and employees work."
Tests of the air surrounding Kelly Elementary School are underway, and results should be available in September or October, according to the San Diego County Department of Health.
Quartarone said a number of children developed rare cancers, which is more proof that there could be cancer-causing agents in the environment.
According to information on the San Diego County Department of Health's website, however, the number of cases of leiomyosarcoma, one of those rare cancers, was not abnormal for the area surrounding Kelly Elementary School. Specific data for the particular area aren't available. John Quartarone said that there were also cases of thyroid cancer and bone cancer.
Epidemiologists say that statistics make it difficult to prove that cancer clusters actually exist.
"What health departments do is look at statistics and determine whether there is a higher incidence in a region," said Regina Santella, professor of environmental health sciences at the Mailman School of Public Health of Columbia University in New York.
"If it seems higher, that still doesn't mean there is some particular cause. It could be a statistical fluke."