Does your natural gas flow through wood pipes?

Is some of the nation's natural gas supply carried in wood pipes? In a Sept. 14, 2010, interview on CNN's Larry King Live, Bill Maher seemed pretty convinced that it's true.

Referring to the Sept. 9, 2010, natural gas explosion in San Bruno, Calif., that killed four and destroyed almost 40 houses, the comedian and social commentator said, "That fireball ticks me off, because we spent $787 billion dollars on a stimulus program when Obama got into office. Now, why couldn't he have said, 'Look, there's a lot of people out of work in this country, and our infrastructure is crumbling and needs repair. Let's just take all that money and put those two thoughts together. Let's have those people who are out of work repair the infrastructure.' Right? What happened to all that money? Why didn't they fix that? An entire town blew up. Do you know that we have pipes carrying natural gas in this country that are made of wood? I'm not joking."

He may not have been joking, but we failed to find convincing evidence that wood pipes carry natural gas in the U.S. today.

Wood did have a place in the history of natural gas distribution -- but that was more than 100 years ago. Today, old sections are occasionally unearthed, but always by accident. Almost always, they are segments that are no longer in use and simply lie next to active lines made of more modern materials such as metal and plastic.

We couldn't establish conclusively that there is no wooden pipe currently in use, because that's unknowable without exposing every inch of the 2 million-plus miles of natural gas pipe in the country. But any wooden pipe that was still working today would have had to remain unnoticed, in good working condition and never replaced for roughly a century, and a variety of sources we spoke to said that is not plausible. So we rated Maher's claim False.