The defendant operated a plant that had refined coal tar for 55 years. It had disposed of its wastes on the site. After the plant closed, the land was purchased by a municipal housing authority. The wastes buried on the site leaked into the groundwater, contaminating the drinking water of nearby cities. The state and the municipalities spent considerable sums of money cleaning up the site. The U.S. government joined the suit, seeking to hold the defendant liable under CERCLA. Was the defendant responsible even though it no longer owned the dump site?