Some of Pennsylvania's natural gas pipelines are 120 years old. Portions of lines also date to the 1800s in Massachusetts. And hundreds of miles in New York state are made of leak-prone cast iron.
Tens of thousands of miles of pipelines that run beneath communities nationwide are old or decaying.
An Associated Press survey found that no states in the parts of the country with the greatest concentration of people and pipes have ordered a safety review in the week since a deadly explosion in California raised public awareness of potential problems.
Officials from Massachusetts to Texas say their inspections are adequate, and they are waiting for federal investigators to determine the cause of the Sept. 9 gas line explosion before deciding what to do.