The rapidly expanding use of radar, television, industrial and medical heating units, communication systems, and many other related devices has raised a question concerning radio frequency electromagnetic radiation effects on man. The presence of radio frequency electromagnetic radiation in the environment was negligible prior to World War II. Now, for the first time in evolutionary history, man is being subjected to appreciable levels of this form of radiation. In 1966 the American National Standards Institute (ANSI) published a document entitled, “Safety Level of Electromagnetic Radiation with Respect to Personnel” (see Appendix), establishing an incident power density safety level of 10 mW/cm2from 10 MHz to 100 GHz for periods greater than 0.1 hour. This standard was formulated primarily from research results on tissue heating considerations. The safety level in the USSR and East European countries is 10 µW cm2 based on their research relating to central nervous system (CNS) and behaviorial effects. This fundamental difference of 1,000 to 1 in the safety standard is due in part to both a different research emphasis and standards philosophy. It is now clear that a comprehensive and scientifically sound standard must be established for the health and safety of the public and that further research is required to clarify the conflicting research data and resulting conclusions which now exist. In 1971 ANSI Subcommittee C95.4 was directed to prepare a report citing research needs for establishing an improved radio frequency safety standard. With Arthur W. Guy as subcommittee chairman, a report was prepared with major contributions from John M. Osepchuk, Albert R. Kall, Sidney Kessler, Sol M. Michaelson, Saul W. Rosenthal, Allan H. Frey, William A. Mills, Harry D. Youmans, James W. Frazer, H. Mark Grove, and Curtis C. Johnson. The purpose of the report was to identify and document the requirements for additional information not available in the literature but needed to modify, refine and improve the present ANSI standard. This paper is based on the subcommittee report.