Dear Mr. Broscious,
Thank you for posting your request on History Hub!
We located an online copy of “Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air and in Water for Occupational Exposure,” NBS (National Bureau of Standards) Handbook 69 as amended August 1963, U.S. Department of Commerce on the website of Oak Ridge Associated Universities.
Should you wish to view a copy through a Federal source, please contact the EPA Docket Center. We also found listings in the EPA National Library Catalog. See Contact Us About the EPA National Library Network for information about accessing these copies. Questions about interpreting and applying the handbook in relation to 40 CFR § 141.66 should also be directed to the EPA.
Legal record copies of material incorporated by reference are also filed at the Office of the Federal Register (OFR) for a limited time period. The OFR encourages people to first contact the standards organization that developed the standard, which in this case would be the EPA. However, if you would like to inspect material incorporated by reference at OFR's downtown Washington, DC location, you must submit a written request and make an appointment for a specific day and time. Your request may be submitted via email at email@example.com. For more information see https://www.archives.gov/federal-register/cfr/ibr-locations.html
We hope this information is helpful.