INVERNESS – New buildings along U.S. 41 and State Road 200 would be covered by proposed regulations designed to protect residents from cancer-causing radon gas.

The area that would be included in the ordinance includes about 32,000 acres – or 7 percent of the land in Citrus County, according to federal soil scientist Paul Pilny.

Pilny delivered the map showing the areas to be covered by the proposed ordinance to county officials last week.

But Pilny said he has known for years that a narrow strip in the eastern part of the county contains phosphate soils that produce radon gas. The map is based on years of analyzing soils across the county.

“This is nothing new,” he said.

The ordinance was developed by a task force of experts on radon gas, including Pilny, St. Petersburg lawyer Tom Reese, University of Florida cancer researcher Dr. Gary Lyman, and Charlie Bradley, head of the county environmental health unit.

The proposed ordinance would require new houses in the high-risk area to be built with methods that limit the amount of radon gas that can seep into the building. For example, plastic liners or under-house ventilation systems could be used to block rising gas before it enters a building.

The ordinance would also require sellers of homes to notify buyers of potential radon problems.

The task force also is proposing a second ordinance that would ensure that fill dirt under houses be free of radon. The ordinance would require operators of borrow pits to obtain occupational licenses and have fill dirt certified as radon-free.

Both measures must be reviewed by the county Planning Commission and then approved by the County Commission. How long it takes to approve the ordinances depends on the political reaction they meet in along that route.

Radon is formed when uranium in phosphate deposits breaks down naturally, especially in areas where the soil has been disturbed by phosphate mining. The odorless, colorless and tasteless gas can cause cancer when breathed over a long period of time.

Radon is harmless when it dissipates into the air. But it becomes a health hazard when it seeps into buildings and concentrates there.

In a recent survey of more than 6,000 homes statewide, Citrus County ranked fifth-highest among the 67 Florida counties for its potential for elevated radon levels.

Radon levels above the federal standard have been found in several Citrus County homes and in Inverness Middle School.