WATERFORD, Conn. -- Authorities have discovered radon at Hemingway Park School in Waterford.

Radon is an odorless, invisible, radioactive gas that can be harmful to health.

What Is Radon? (Risk Charts, Myths, More Information)

Channel 3 Eyewitness News reporter Hena Daniels reported elevated levels of radon were found in four rooms in the school of 330 children. Radon can seep into buildings from the soil underneath and via pipes and cracks. High levels of radon can pose a significant risk in developing lung cancer.

According to the state Department of Public Health's assistant superintendent, Todd Lofrese, the levels found at the school are not dangerous.

"We want to make sure students and staff are in a healthy environment, and they assured us levels were insignificant based on time and levels of radon," Lofrese said. "A system needs to be installed that removes the radon and exhausts it through the roof of the building."

For now, the four classrooms are not being used until the radon is removed.

Some parents with whom Eyewitness News spoke said they are not worried.

"We've been well informed and we feel assured there is no danger to our kids," said Dana Barr, of Watertown.

"They were working on the problem and it won't effect the children because they weren't in the classroom long enough to be affected," said Lorraine Pavanel, of Watertown.