From the minute police entered Joseph C. Callahans Greenfield Hill home, he freely discussed the array of bomb-making chemicals he collected in his house.When they asked about some large containers in his garage, which contained about a hundred pounds of a substance Callahan readily identified as ammonium nitrate, he couldnt have been more helpful.”Thats the chemical used in the 1993 World Trade Center bombing,” police said he explained to them.Then he pointed to vats that he said contained chemicals used in the Oklahoma City bombing.
