KANTELE FRANKOWESTERVILLE, Ohio (AP) â¿¿ Reports of lightning-related fires and gas leaks in at least a dozen states have raised concerns about the use of flexible gas lines made of corrugated stainless steel tubing and have led to lawsuits, studies and efforts to better track the incidents. Manufacturers have defended the plastic-coated metal tubing, known as CSST, which has become increasingly common in new homes since it was introduced domestically more than two decades ago. Fire officials and researchers are trying to determine whether to blame a faulty product, unsafe installation or something else for the blazes. Four homes caught on fire in central Ohio over a stormy 12-hour period this summer. Genoa Township Fire Chief Gary Honeycutt said he believes lightning struck at or near the homes, and the electrical charge traveled along the CSST before jumping to a less resistant pathway nearby such as a metal ventilation duct. It then punctured a hole the size of a pencil tip in the tubing and created a gas leak that could ignite, he said. One of the fires charred the ceiling in the lowest level of Michael Wagner's dream home, a two-story property near a country club and golf course in an area where farmland has been turned into neatly manicured neighborhoods of newer homes. "It had been burning the joists much like a blowtorch," said Wagner, whose family moved into the home a few weeks before the fire and has been displaced for months because of smoke damage. The home passed inspection without problems, they said, but they later learned lightning had struck it and created a gas leak in 2004. Firefighters and gas providers point out that the fires seem to occur with an unusual combination of factors â¿¿ a newer building that has CSST, a lightning strike in just the right place, the puncture of the tubing and the spark to ignite the gas. Most of the Ohio fires were in the central part of the state, though it's possible there are others that haven't been linked to the tubing because the reports didn't include that detail.