Last year, an engineer discovered that the back of the house had sunk an inch. A company hired by Centex to shore up the house found the underground debris. Soon after, the county's environmental protection department tested the ground beside the house and found three areas with potentially explosive levels of methane gas. The tests found no methane inside the house. Officials with the county's building standards department tested inside the house again last month, with the same result.
Underground methane can seep into a house, county environmental officials say.
If the concentration of methane in an enclosed space is between 5 percent and 15 percent, it can explode in the presence of a spark or flame. Much higher concentrations of the gas could asphyxiate someone, but that rarely happens, they say. But the Wests aren't taking any chances. They have installed two methane detectors, one in the bedroom and one next to the water heater in the garage. Terrified, she says, she ran outside only partly clothed.