"We want to be diligent and overly cautious just to make sure there isn't anything here, but we don't want to panic," principal Jerry Block told CNN Newsource affiliate KCAL/KCBS.
The news, though, is still unsettling to parents. The school brought them in for an informational session about the issue on Tuesday.
Cassandra Wiseman, whose son has been so sick with asthma and migraines, is upset.
"It's appalling. You think you are doing the right thing then you're suddenly, you have this total self-doubt that you're not at all," Wiseman said. Asked what she will do next if her son's health problems continue, Wiseman concluded, "I don't know what to do. I'm just a mother."