The state fire marshal’s office investigates several gas explosions each year, and it said most of them could have been prevented.

An explosion can be the result of a tiny gas leak that homeowners cannot see and may not smell.

“They assume, ‘I don’t smell anything, therefore I’m safe,’ and that simply is not the case,” said Wanda Fillner, an advocate for gas detectors.

A weak smell does not mean it’s a small leak. Dangerous amounts may escape with little or no odor.

Gas companies said that a person’s nose the best detection tool because an odor is added to natural gas so it can be detected.

“It smells like a rotten eggit’s an odorant that’s added. It’s a little different than the one that’s added to natural gas,” said Deb Grooms, of the Iowa Propane Gas Association.

Experts said that if a propane or gas leak is suspected, do not touch a light switch, do not make a call on a cell or home phone. They said to use a neighbor’s phone to call for help.

“Our companies do provide … emergency services for the detection and investigation of gas leaks and that’s 24-hour, 7-day-a-week service,” said Mark Douglas, of the Iowa Utility Association.

Homeowners should also check their lines before digging in the dirt. Digging a fence into a gas ine is what caused a house explosion in Richland that killed seven family members.

Bev Gartner survived with burns over 70 percent of her body, but now she has four gas detectors in her home near each appliance. Gas detectors sound an alarm when gas is present. Some devices detect carbon monoxide, propane and natural gas.

Experts said that homeowners should never touch their own appliances, but should leave it to the professionals.

Polk County was one of the first communities in the nation to require gas detectors in new construction projects where propane is used.