WASHINGTON - The Senate has given final approval to a bill that doubles the maximum fine for pipeline safety violations and adds penalties for obstructing safety investigations, but sidesteps several key recommendations arising from investigations of a deadly natural gas explosion and two high-profile oil spills over the last two years.

The compromise bill cleared the Senate late Tuesday by a voice vote and now goes to the White House for President Obama's signature. The House approved the same measure Monday. The measure is the result of weeks of negotiation between advocates of tougher safety rules and lawmakers who wanted to avoid overburdening industry with unnecessary regulation.

Communities that neighbor pipelines "can rest a little easier knowing that Congress has implemented tougher safety rules," Sen. Jay Rockefeller (D., W.Va.), chairman of the Senate Commerce, Science and Transportation Committee, said in a statement.

Safety advocates said the bill is a modest step forward. They complained that it doesn't follow through on several key recommendations arising from investigations of a 2010 gas pipeline explosion that killed eight people, injured dozens of others and damaged or destroyed more than 100 homes in a suburban neighborhood near San Francisco, as well as two recent high-profile oil spills in Michigan and Montana.

The United States has approximately 2.3 million miles of pipelines that transport oil, natural gas, and hazardous liquids. Since 2006, there have been about 40 serious pipeline incidents each year that resulted in a fatality or injuries.

The bill doubles the maximum fine for pipeline safety violation to $2 million and authorizes the Pipeline and Hazardous Materials Safety Administration to hire 10 more safety inspectors.