For environmental reporters, pipelines are a frequent source of major news stories. Enterprising journalists may want to find nearby pipelines before they leak or blow up. The National Pipeline Mapping System is a basic tool that can help.
Maintained by the Pipeline and Hazardous Materials Safety Administration (PHMSA), the mapped database is searchable and online here. Portions of it are open to the public. It is viewable only on a county-by-county basis.
While the resolution and accuracy of the system may leave something to be desired, it is national in coverage and useful for general reconnaissance on larger-diameter pipelines.
There are other data resources for covering pipeline issues — many listed in the WatchDog of August 18, 2010.