Illnesses including cancer, headaches, rashes and unexplained hair loss among teachers at a California high school have prompted the school district to bring in environmental testers.
A group of teachers believes a 2011 construction project helped lead to the illnesses that they believe affect up to one-third of the staff at Malibu High School in Malibu, Calif., CBS Los Angeles reported.
According to The Malibu Times, 20 middle and high school teachers signed the letter that said three faculty members have been diagnosed with stage 1 thyroid cancer within the past six months, another three have thyroid problems and seven teachers suffer from persistent migraines.
The letter also added that other teachers have been treated for unexplained hair loss, skin rashes, bladder cancer and several respiratory illnesses.
Malibu High School enrolls more than 1,100 middle and high school students in grades 6-12.
The teachers think the illnesses stem from the Santa Monica-Malibu Unified School District hiring contractors to remove more than 1,000 yards of dirt from campus that was allegedly contaminated with waste chemicals called polychlorinated biphenyls (PCB), lead, volatile organic compounds and pesticides. They also cited construction work on several classrooms they believe have mold problems.
A 2010 report ahead of the construction cited by The Malibu Times eyed PCBs as the primary hazard on campus.
PCBs were banned in the U.S. in 1979, according to the Environmental Protection Agency, but remain in contaminated soil where they can enter the food and water supply in low levels.
"We are all exposed to PCBs unfortunately," Dr. Kenneth Spaeth, director of the Occupational and Environmental Medicine Center at North Shore University Hospital in Manhasset, N.Y, in an interview with CBSNews.com.
There are more than 200 types of PCBs, with some linked to more severe health effects than others. They can cause a wide range of health problems to areas of the body such as the immune system, reproductive system, nervous system, endocrine system, and liver, and have been associated with cancers, diabetes, heart disease and neurodevelopment problems in children.
The school said it began testing air and surfaces for mold and other contaminants last month, and district superintendent Sandra Lyon told staffers in an Oct. 4 memo that the district hired "a highly qualified environmental consulting firm to investigate these concerns and to recommend corrective action should any be identified." The firm will re-examine soil tests previously taken from the removed dirt.
Lyon said parents should not worry about sending their kids to class, telling City News Service, "We know they are safe, just as much as you know that your house is safe."
When groups of people get sick, it's common to look at recent changes in their environments as a potential cause for their illnesses. However, actually linking environmental changes to a disease cluster -- cancer specifically -- can be very difficult, explained Spaeth.
"It's a complicated process, with a fair amount of investigative work that has to be done," he said.
He's participated in investigations of disease clusters in New York City. There are two crucial parts for investigators to focus: The first involves testing how much chemical exposure is in the environment, and in this case with teachers reporting illnesses, Spaeth suggested that tests should also be done inside the school.
If those tests find levels of chemicals high enough to warrant a health concern, that's when the local or state health department may step in and start going through medical records to search for evidence of a disease cluster. But the results have to match: There are four types of thyroid cancer, for example, and not all forms are equally attributable to an environmental cause.
"It's a complicated thing to do," said Spaeth. "A specific diagnosis becomes really important."
Spaeth, an environmental toxins expert, has no involvement in the Malibu case. He said investigators would want to know which PCBs and compounds were found, and at what levels to help determine if there is a health issue. That's why it's so important for investigators to first determine the path of exposure before concluding a disease cluster is present.
"Until you know if PCBs are present inside the school -- in it's water supply or air -- that connection is a question mark," he said.
Seth Jacobson, whose son goes to class in one of the rooms in question, told The Malibu Times he's unhappy that parents were not informed that environmental testing began recently at the school.
"We should have known about it, the district should have told us about it. It's serious business," he continued. "Whether or not it turns out to be a problem. The fact that they've engaged a firm to do an environmental analysis of air quality around our building, that's a significant issue for children."