The Lake County Health Department is offering short-term radon testing kits for $10. Cost includes return postage, lab analysis and interpretation by health department staff. Residents are urged to test their houses for the colorless, odorless gas in January during National Radon Action Month, when indoor radon levels are highest. Radon is a radioactive gas naturally found in rock and soil and moves into houses through cracks and holes in the foundation. It is the leading cause of lung cancer among nonsmokers, killing 21,000 people each year. For information or to request a kit, call (847) 377-8020 or visit http://www.lakecountyil.gov/2450/Radon.