The county recently learned it can get up to $750,000 from the Federal Emergency Management Agency to pay for the construction of monolithic domes -- essentially steel-reinforced concrete igloos -- to serve as tornado shelters for county mobile-home parks. The structures are a more common sight along the Gulf Coast.

Their shape and seamless construction make them ideally suited to resist high winds. "There's no flat wall for straight-line winds, or the circular winds of a tornado, to push against," said Jim Mickey, the county's environmental planner.

The construction process starts with inflating a large balloonlike form that serves as a layer of weather-proofing after construction. A steel skeleton is then built inside the balloon and filled with insulation and a 4- to 8-inch layer of sprayed concrete. The outer layer is finished with stucco.

The buildings can be as spartan or as lavish as the owners desire, and some have been used to house churches, schools and gymnasiums.

Mickey, who wrote the grant application, said the two structures being built this summer are the first in the nation to be used as shelters in a mobile-home community.

About 50 percent of tornado-related deaths in the United States occur in manufactured homes, according to a report by Harold Brooks, a research meteorologist with the National Oceanic and Atmospheric Administration's National Severe Storms Laboratory. Brooks said 633 people died because of tornados between 1999 and 2008, and 318 of them were in mobile homes.

Ron Thomas Sr., who with his son owns Summit Ridge Estates, one of the two mobile-home parks where the domes will be built this summer, disputes Brooks' research. He said that since the mid-1990s, mobile homes have been manufactured to much higher standards because of regulation by the U.S. Department of Housing and Urban Development.

Thomas said all the homes in his Pataskala community are less than a decade old and conform to the safer standards. He said the family agreed to build the dome because it will double as an office and community center and could be built for pennies on the dollar.

The park's 50-foot-diameter dome will be able to hold 315 people, or about three times the park's current occupancy. Of the 39 mobile-home parks contacted by the county, Thomas is one of two owners who have agreed to pay the 25 percent local match to get the federal money. Construction is to begin in the next few weeks.

That dome is expected to cost about $229,000. The second, a 32-foot-diameter building at Wilkins Park in Newark, will cost about $93,000. Mickey said the county hopes that more mobile-home-park owners will agree to participate in the program once they see the first two structures. If the money isn't spent by July 31, 2010, it will go back to the federal government.

Mickey said the domes would offer park residents almost total, short-term protection in bad weather.

"Folks will be in pretty close quarters, but at most for a couple of hours," he said. "There's not much we can do to reduce property damage, but at least we can protect people's lives."

jjarman@dispatch.com