SAN FRANCISCO — Pacific Gas & Electric Co. officials are acknowledging that they may never be able to find some of the documents for the utility's older natural gas pipelines.

In a filing with the California Public Utilities Commission on Thursday, PG&E said it cannot satisfy a state order to come up with what utility officials termed "traceable, verifiable and complete" records on its entire pipeline network.

The CPUC ordered the utility to turn over the documents after the explosion last fall in San Bruno that killed eight people and destroyed dozens of homes.

Federal authorities have since determined that the pipeline failed at a welded seam.

The San Francisco Chronicle reports that PG&E officials are asking state regulators to accept what was termed "assumptions" about some of its older pipelines.