Summary: Pursuant to a congressional request, GAO provided information about the Environmental Protection Agency's (EPA) approval of the construction of a hazardous waste incinerator in East Liverpool, Ohio. GAO noted that: (1) Ohio, which has primary responsibility in regulating the facility, considered such siting criteria as floodplain and seismic restrictions, population density, property values, and health risks, before approving the incinerator permit; (2) EPA properly followed federal regulations when it did not consider location characteristics in approving a permit modification request; (3) although the firm first received permits to construct the facility in 1983 and 1984, permit conditions will fully meet current performance standards; (4) EPA is conducting a risk assessment of the facility to evaluate potential health effects due to concerns about the use of outdated and limited approaches in previous risk assessments; and (5) EPA and state monitoring of such facilities, which is critical to ensure safe operations, have historically been inadequate, and enforcement actions have been untimely and inappropriate.