The California Public Utilities Commission (CPUC) has imposed a fine of $1.6bn on PG&E Corporation over a gas explosion that occurred in 2010.
PG&E’s natural gas transmission pipeline in San Bruno exploded due to a faulty weld on the pipeline, killing eight people.
The company is being fined for 2,425 violations of federal and state safety rules and still faces approximately $1.13bn in federal criminal fines for the blast.
It has, however, announced plans to invest around $2.8bn to improve pipeline safety.
As part of its safety measures, PG&E has conducted advanced pipeline safety testing, replaced pipes where necessary and installed more than 200 new automated or remotely controlled emergency shut-off valves.
The company is also employing a new gas leak detection technology that is 1,000 times more sensitive than before in order to help find and fix leaks before they become a problem.
Additionally, the company decommissioned more than 800 miles of remaining cast-iron pipe in its system, and replacing it with more efficient and seismically sound pipe.
PG&E chairman and CEO Tony Earley said: "Since the 2010 explosion of our natural gas transmission pipeline in San Bruno, we have worked hard to do the right thing for the victims, their families and the community of San Bruno.
"We want our customers and their families to know that all of us at PG&E have committed ourselves to a goal of transforming this company into the safest and most reliable energy provider in America.
"We’ve hired some of the best experts in the country to help guide this effort and we’ve supported it with billions of dollars in shareholder funded investments in gas safety.