And the percentage of dangerous liquids recovered by pipeline operators after a spill has dropped considerably in recent years.

Instead of drawing gas directly from those offshore fields, pipeline operators have begun tapping storage sites along the coast to meet demand, he said.

Known also as intermediate stations, these facilities allow the pipeline operator to deliver part of the product being transported.

The compressed natural gas will be used in the county's natural-gas-powered vehicles, with any surplus being sold to pipeline operators.

The pipeline operator may advise on behalf of the shipper.

The pipeline operator must distribute the completed returns as follows:

The pipeline operator must prepare two returns for each calendar month.

The pipeline operator must complete the returns for each calendar month and must distribute them as required by section 9 of Notice 179.

Houston is home to 13 of the nation's 20 largest natural gas transmission companies, 600 exploration and production firms and more than 170 pipeline operators.

A government pipeline planned by Transneft, a pipeline operator, is going forward, but at a slow pace.