[en] The environmental monitoring program, which began in 1980, was continued in 1988 at the former Middlesex Sampling Plant (MSP) site, located in the Borough of Middlesex, New Jersey. The MSP site is part of the Formerly Utilized Site Remedial Action Program (FUSRAP), a Department of Energy (DOE) program to decontaminate or otherwise control sites where residual radioactive materials remain either from the early years of the nation's atomic energy program or from commercial operations causing conditions that Congress has mandated DOE to remedy. The environmental monitoring program is carried out by Bechtel National, Inc. (BNI), project management contractor for FUSRAP. The monitoring program at the MSP measures radon concentrations in air; external gamma radiation levels; and uranium and radium concentrations in surface water, groundwater, and sediment. To verify that the site is in compliance with the DOE radiation protection standard (100 mrem/yr) and to assess its potential effect on public health, the radiation dose was calculated for a hypothetical maximally exposed individual. Results of the 1988 monitoring show that the MSP is in compliance with applicable DOE radiation protection standards and with applicable requirements specified by New Jersey Department of Environmental Protection groundwater permits. 17 refs., 15 figs., 21 tabs