St. Paul, Minn. — Minnesota has some of the strictest rules in the nation for mitigating radon gas in homes. But the state Department of Health is concerned the rules don't go far enough, and it's now asking builders to voluntarily install attic fans that can draw out the toxic gas.

The naturally occurring gas is odorless, invisible, and found in soils throughout Minnesota, and the U.S. Environmental Protection Agency estimates that as many as 800 Minnesotans die each year from radon-induced lung cancer.

Even so, only a few builders have signed on to the MDH program, which is aimed at augmenting the passive radon vents required by Minnesota law.

Dean Hanson of Hanson Builders, who has been in business for 32 years, said the agency offered to give him a discount on radon-venting fans if he agreed to install them in all of the new homes he builds.