[en] This report discusses those technical aspects of the operation of the Medium Energy Accelerator at NIKHEF-K which affect the environment. The accelerator produces an electron beam with a maximum capacity of 300 kW and, as by-products, intense gamma and neutron radiations. These radiations can contaminate components of the accelerator and the direct surroundings. The electron beam can also generate ozone in the air. The accelerator produces a small quantity of radioactive waste itself and research in the chemistry department also leads to the production of radioactive waste. These wastes are stored temporarily and transported for treatment/storage elsewhere in Holland once a year. (Auth.)