NuStar operations suspended indefinitely

CROCKETT, Calif. (KGO) -- Despite the amount of black smoke that poured out of the NuStar's burning energy storage tanks, the company claims its air samples found contaminants at or below detectable levels.

NuStar says its engineers are inspecting the structural integrity of the remaining tanks.

VIDEO: Explosion at NuStar Energy facility caught on camera

Operations at the site have been suspended.

A cause of Tuesday's fire has not been determined.

Get the latest on the fire at NuStar Energy in Crockett here.