Three contractors were injured late Tuesday in a flash fire at BPs 337,000 bpd Whiting refinery in Indiana, news agency Reuters reported.
When the fire ignited, the injured contractors were performing maintenance work on a 105,000 bpd hydrotreater, according to the report.
Industry analysis group IIR Energy said work on the hydrotreater was suspended after the fire, but is still expected to conclude by early October. Other refinery operations were not affected, Reuters said.
BP said the three contractors were in stable condition at a local hospital. Two were being treated for burns and one for smoke inhalation.
The fire was quickly extinguished by on-site response crews, the company said.
The hydrotreater maintenance is part of the Whiting refinerys $4 billion upgrade project to enable it to better process heavy Canadian crudes.
The upgrading project is scheduled to be complete by late 2013.