NIKISKI (AP) -- A small explosion at the Tesoro Alaska Petroleum Co. refinery in Nikiski Wednesday afternoon caused no injuries and didn't slow production, company officials say.
Welders were installing a metal liner in an oily water drainage canal at the time of the explosion, said Tesoro spokesman Ron Noel.
''At this time I can't tell you exactly what happened, but vapors may have traveled along (the canal) and ignited in the sump,'' Noel said.
He said the explosion in the lead-lined underground sump chamber was like a flash fire.
''It made a big 'whump' noise,'' Noel said.
He said there was no subsequent fire associated with the blast and operations at the refinery were not affected.
''There were no injuries, no fire and no spill,'' Noel said.
The Nikiski Fire Department responded to the blast, but returned to the station shortly after arriving.
The company is investigating, Noel said.
Peninsula Clarion ©2013. All Rights Reserved.