The U.S. Senate unanimously approved a pipeline safety bill on Monday that would require strength-testing of old pipes and hike fines for safety violations after a series of accidents and explosions.

The legislation was sparked by an explosion a year ago in San Bruno, California, on a line owned by Pacific Gas & Electric Co . The explosion destroyed a neighborhood and killed eight people.

Investigators blamed the blast on weak regulatory oversight. The National Transportation Safety Board said the preventable rupture was caused by defective welds on pipeline laid in 1956.

This bill strengthens oversight and addresses long-standing safety issues that leave the public vulnerable to catastrophic pipeline accidents, said Senator Frank Lautenberg, a New Jersey Democrat who co-sponsored the bill.

The United States has about 2.3 million miles of pipelines that move oil, natural gas and other hazardous liquids.

The bill requires automatic or remote-controlled shut-off valves to prevent oil spills and natural gas explosions, requires faster notification to the government of accidents and leaks, and boosts funding to add more pipeline inspectors.

BOOM TIME FOR NATURAL GAS, SHALE OIL

The bill comes amid massive growth in U.S. natural gas and shale oil production.

This week, Kinder Morgan Inc said it would buy El Paso Corp , a $21 billion deal combining the two largest natural gas pipeline operators in North America and creating an 80,000-mile network of pipeline.

But public scrutiny of the potential environmental risks of pipelines has also intensified.

The Obama administration is considering approvals for TransCanada Corp's $7 billion Keystone XL pipeline, which would carry crude oil to Texas from Canada -- a project opposed by environmental groups.

A panel in the U.S. House of Representatives passed a similar pipeline bill on Sept. 21, which still has to be voted on in the full House.

That bill would require U.S. oil pipelines to be buried deeper when crossing waterways to avoid the kind of leak that polluted Montana's Yellowstone River in July when a pipeline owned by Exxon Mobil Corp ruptured.

One major industry group said it hopes Congress can send a final bill to be signed by President Barack Obama by the end of the year.

This legislation updates and improves policy in several areas, including integrity management and damage prevention, said Don Santa, chief executive of the Interstate Natural Gas Association of America, which represents pipeline operators.