Respondents discharged contaminated groundwater and stormwater from certain outfalls without a permit and failed to fully investigate the reason for elevated metals levels in stormwater, as required by the facility's NPDES permit. The AOC requires the Respondents to eliminate unauthorized discharges at the Worcester facility by (a) relining a subsurface pipe in order to eliminate the infiltration of contaminated groundwater into the pipe; and (b) applying for permit coverage for unauthorized stormwater outfalls. The AOC also requires the Respondents to continue to investigate the reasons for elevated metals levels in stormwater by proposing for installation control measures to minimize metals loadings in stormwater discharges from the facility and conducting monitoring to evaluate the effectiveness of those control measures.