This is an Administrative Order pursuant to CERCLA 106(a) and RCRA 7003 issued to Emhart Industries and Goodrich Corporation (Respondents). The Order directs the Respondents to investigate the nature and extent of soil and groundwater contamination in an 160 acre area of the Rialto-Colton-Fontana Site in Rialto, California. Respondents historically manufactured munitions and rockets on the 160 acre area. Groundwater immediately downgradient of the area is contaminated with perchlorate and trichloroethylene (TCE) impacting numerous public drinking water supply wells.