but epidemiologyells us in n a commununity there may be e an unusual pattern of disease, either defined in space,, geographically, or inn time e t develops over a period of time. whenen that happens we call it cluster r and a c cluster is a clue, a piece of evevidence tha somemething may be happening in that comommunity. that's what happened in toms rivever. >> becauause of the unusual number of rare childhood cancers, the community demanded answers. and the finger pointed back to ciba geigy and the toxic waste drums union carbide dumped at the farm.m. a decade earlier, two wells at e f farm had been tested and trichloralethylene was found. >> once it was found coming from the farm, the government absolutely dropped the ball. that ever should have let happen and let the people drink that water. >> the e.p.a. and union carbide adopted a remediation plant. it's a superfund site. we will let these chemicals go into the public drinking waters and aerate them out and then the water will be safe to drink. someone said, why don't we put carbon filters on that water just to make sure nothing ge