The criteria and the recommended standard based thereon prepared to meet the need for preventing occupational diseases arising from exposure to carbaryl (63252) are presented. Occupational exposure to carbaryl is defined as exposure to airborne carbaryl, the 1- naphthyl ester of N-methylcarbamic-acid or 1-naphthyl-N- methylcarbamate, at concentrations less than or equal to the action level. The standard is designed to protect the health and safety of employees for up to a 10 hour work shift, 40 hour work week, over a working lifetime. Exposure to carbaryl at concentrations less than or equal to the action level shall not require adherence to the recommended standard except for certain sections. Biologic effects of exposure are given with details of the extent of exposure, epidemiologic studies, correlation of exposure and effect, environmental data, exposure control, sampling and analysis, standard development, work practices and research needs.