The inspector general's office said Thursday that it will add more than a dozen lines of inquiry, some requested by Congress and others raised by a review of the spill by the Interior Department.
An EPA-led contractor inadvertently released 3 million gallons of wastewater tainted with heavy metals from the Gold King Mine on Aug. 5 during cleanup operations. Rivers in Colorado, New Mexico and Utah were contaminated.
The inspector general will also look into what kind of legal protection EPA gave the contractor and whether that affected the way the work was done.
