EHD Associates Incorporated is a subcontractor research company specializing in chemicals. They were hired by a chemical company, Danforth Chemical, to test an experimental pesticide named Zilithion. They in turn hired a consultant, Seth Millstead, to test it on poor children residing in an apartment. Because of their poor handling of the tests, twelve people, including Detective Olivia Benson, were poisoned by the pesticide, with one contracting cancer as a result of long-term exposure.