Radon, a byproduct of radioactive decay, is the second-leading cause of lung cancer in the United States. And Minnesota is ranked fourth-highest in the nation with highly dangerous levels in many homes. Thanks to the work of Extension housing technology specialists, Minnesota's homes are much safer from this threat. Extension experts teach builders and other housing-related professionals how to prevent and fix radon problems. Their goal is to improve the long-term quality, efficiency, environmental health and durability of residential and other buildings in Minnesota and other cold-climate regions. Due in part to Extension's teamwork, Minnesota was first to establish a statewide building code to reduce radon in new homes.