After months of hand-wringing among environmental regulators, company executives and environmentalists, Indiana has approved the much-criticized BP Whiting air construction permit.

The permit allows the refinery to construct equipment to modernize its facility, the Indiana Department of Environmental Management said Thursday.

IDEM said comments from the public and the U.S. EPA affected the final permit, adding monitoring, testing and record keeping requirements.

Several individuals and groups spoke out against the proposed air permit. Under the permit, the refinery would decrease emissions of four pollutants but would increase releases of sulfur dioxide, particulate matter and lead.

Critics complained IDEM did not allow ample time to properly review BP's application. BP submitted draft construction and operations air permit applications to IDEM Oct. 31. Draft permits were released to the public Feb. 5.