SILVERTON — Three days after EPA workers triggered a huge blowout at a festering mine in southwestern Colorado, a mustard-colored plume — still fed by 548 gallons leaking per minute — stretched more than 100 miles, spreading contaminants including cadmium, arsenic, copper, lead and zinc.

Environmental Protection Agency regional chief Shaun McGrath on Saturday conceded that federal officials know the levels of the heavy metals in Cement Creek and the Animas River but would not reveal early testing results. "Those data sheets have not been finalized by the scientists," McGrath said. "As soon as we are able to release them, we will."