Nearly a year after teachers at Malibu Middle and High Schools brought up their concerns over toxic classrooms contaminated with cancer-causing chemicals found in old caulking, parents are worried about sending their children back to school next Tuesday. One of those parents is Cindy Crawford, who is offering to pay for testing to ensure the carcinogens are gone.

At a rally yesterday for Malibu Unites, a nonprofit that lobbies for safe and healthy Malibu schools, parents—including actors Josh Malina, Ed Begley, Jr. and supermodel Cindy Crawford—advocated for all caulking to be tested in classrooms built before 1979. The carcinogen, known as PCBs, is found in old caulking and can contaminate soil and air. (Malibu schools started experiencing problems during construction.) Even though the EPA gave the school an all clear after cleaning and testing, some of the caulk still remains, Fox LA reports. Malibu Unites is concerned that surface wipe and air testing aren't providing a clear picture of contamination while the potentially dangerous caulk is still in the schools.

And this carcinogen is no joke. Some who were exposed were diagnosed with cancer and others fell ill. Crawford and her husband Rande Gerber have volunteered to pay for the testing themselves to make sure the classrooms are safe. "The caulk is still there and so my feeling is to test the caulk and if it needs to be removed, lets remove the caulk," she said. "It doesn't seem like rocket science to me."

The parents said that the school told them that everything was now fine, but they're not convinced. Several parents are planning on keeping their children home next week, including Malina.