SAN FRANCISCO (AP) -- California regulators have refunded $375,000 to PG&E over concerns the fine payment could jeopardize a potentially larger penalty against the utility for the deadly San Bruno pipeline explosion.

The San Francisco Chronicle reported that the Public Utilities Commission's Safety & Enforcement Division sent a letter to PG&E on Friday that withdrew the citation and included a check for $375,000.

The Safety Division imposed the fine earlier this month after an audit determined that PG&E for decades lacked a procedure to systematically monitor its gas pipelines.

According to the Chronicle, attorneys involved in the San Bruno case are still worried PG&E would use the $375,000 charge to challenge a potentially multi-billion-dollar fine for the 2010 blast.

That's because both stem from many of the same gas system problems.