The Environmental Protection Agency is warning residents of Sedgwick and Butler County of a potential indoor air problem involving carbon dioxide and methane.
Bottom line from the EPA: Ventilate your basement and lower areas in your home, and if you sleep down there, sleep somewhere else until the ground dries out.
EPA and local environmental officials are alerting people that recent rains may have sealed the soil around homes.
Soil gases, such as methane and carbon dioxide, that would normally escape into the air, may instead seep into basements through cracks in the foundation or walls or gaps around service lines.
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Elevated levels of methane or carbon dioxide could cause danger, either from oxygen deprivation to people, or to pilot lights going out and flammable gases gathering in homes.
The EPA issued its warning Friday because the ground is saturated from recent heavy rains. The warning is based on air sampling done during flooding in September of 2008.
"When we have high periods of rain, ground can be saturated, and may push natural gases into crawl spaces and basements of homes," said Kay Johnson, director of environmental services for the city of Wichita. "We want people to be aware of what's going on."
No one has been killed or injured, she said, "But we're trying to make sure we don't have anything like that."
She said investigators became aware of the problem in September 2008 when residents in Sedgwick County called their gas companies after they found that they could not re-light their pilot lights. Officials checked 49 homes and found 13 of them with oxygen-deprived lower areas, Johnson said.
The EPA mentioned the Prairie Lakes area in Valley Center as the place where it found much of the problem, but Johnson said gas company investigators have found similar problems in El Dorado, Andover, and other areas of Butler and Sedgwick counties. She does not think it's a problem localized to Prairie Lakes.
EPA investigators plan to check homes in Sedgwick and Butler counties, and to a lesser extent in Sumner and Harper counties, which each reported a single case.
She said investigators do not know whether this problem has a natural or man-made cause yet but are investigating. The problem is expected to go away once the soil dries out but that until then, people need to ventilate their homes.
EPA officials said that because carbon dioxide is odorless and colorless, families living in homes affected by high concentrations of gases usually are not immediately aware of a problem. They learn of it sometimes as a result of head or body aches, labored breathing and exhaustion; or the pilot light won't re-light.
The EPA said in a statement that the best short-term remedy for stopping gas intrusion is to fill cracks, joints, gaps and openings in walls, floors, and around service lines with impermeable seal, such as such as polyurethane caulk or hydraulic cement. Johnson said people can also buy wall mounted monitors that analyze oxygen and carbon dioxide gas, but those can run $2,000.
Opening a window downstairs — and avoiding sleeping in basements even during mild flooding — can solve the problem.