 The tannery used PCE as a degreasing agent, beginning in the 1960s; by 1976, of this chemical were used by the tannery each year, with up to on the premises at any one time.PCE was leaking out of the drums it was carried in, first by being spilt when it was tipped into the degreasing machines and second by leaking from near-empty drums.Although these spills were individually small, it was estimated around of PCE were spilled each year.