SOUTH LAKE TAHOE, Calif. — Three classrooms and a custodial office in Zephyr Cove Elementary School will be retested for radon in the next two weeks after December test results showed elevated levels in these areas.

George Whittell High School will also be tested for radon at the same time because it was not tested in 2009 due to a boiler system replacement.

Test results for both schools could be available in three weeks, said Holly Luna, chief financial officer for the Douglas County School District.

Radon is a colorless, odorless, tasteless radioactive gas that is the second leading cause of lung cancer in the United States.

EPA guidelines do not require anyone to vacate the rooms with elevated levels, Luna said.

In March of 2009, DCSD contracted with Colorado Vintage Companies to perform radon testing on all school sites and support facilities. After that test 11 rooms in the school district were found to have radon levels above the Environmental Protection Agency's guideline of 4 picocuries per liter. By April 2009 the district retested and all rooms reported below the recommended level. Whittell was not included in these testings because of the boiler system replacement.

Those 11 rooms were retested again in December, which is when the elevated levels were found at the elementary school.

The results of the upcoming tests will be posted at http://dcsd.k12.nv.us when they are available.