A gasoline-producing fluidic catalytic cracking unit was not running on Monday after a fire broke out Sunday at Valero Energy Corp’s 335,000 barrel per day (bpd) Port Arthur, Texas, refinery, Reuters News service reported, citing sources familiar with plant operations said.

The fire was stemmed from a hole in the FCCU’s fractionator, the sources said.

The time needed to repair and return the unit to normal operations was unknown on Monday, according to the sources.

Valero declined to comment.