WASHINGTON — Every building operated by Montgomery County — from recreation centers to libraries — will undergo radon testing.

The move comes after the County Council passed a bill that requires radon testing when single family homes are sold. This year, 28 county school buildings — including 26 actual schools — had elevated radon levels.

David Dise, the county’s general services director, said there’s no requirement to test buildings for radon, but his office is moving forward after the school system’s radon results.

“There are about 200 buildings that will need to be tested,” Dise said. “We will begin with child care and public health buildings, followed by recreation facilities, libraries, public safety and office buildings.”

Radon is an odorless, colorless gas that the Environmental Protection Agency identifies as a known carcinogen.

Dise said if tests show “positive” readings, a second test will be performed. If necessary, remediation will be carried out.

In a statement, Interim Schools Superintendent Larry Bowers said immediate steps will be taken to correct the problem if radon levels are higher than what the EPA allows.

A radon monitoring program will be developed with guidance from experts and the EPA, and test results will be available on the MCPS website.

WTOP’s Kate Ryan contributed to this report.