SAN FRANCISCO Federal prosecutors quietly filed court papers Tuesday that may save a utility company from paying $562 million in fines for a pipeline explosion that killed eight people in 2010.

The stunning move, as a jury in a criminal case against Pacific Gas & Electric deliberated for a fourth day, means the company now faces a maximum federal fine of $6 million, instead of $562 million, if it is convicted in one of the worst disasters of its kind in history. The jury is considering 13 criminal charges stemming from the blowout and fire that destroyed 38 homes in suburban San Bruno.

Pursuing the half-billion-dollar fine would have required prosecutors to present the jury with complicated instructions to determine how much the utility had saved by breaking safety regulations, according to The Mercury News .