Dear Mr. Popkin,
We hope this is helpful. Best of luck with your research!
We suggest that you request a copy of his Official Personnel File (OPF). OPFs and medical information for individuals who worked for the U.S. government in a civilian capacity before 1952 are in the custody of the National Archives at St. Louis (RL-SL). Please email RL-SL via email at firstname.lastname@example.org and include the full name used during Federal employment, date of birth, Social Security Number (if applicable), name and location of the employing Federal agency, beginning and ending dates of Federal Service. If there is any information requested that you do not know, you may omit it or provide estimates (such as for dates), but the more information you provide, the easier it will be to locate the correct file. For more information, the web site is https://www.archives.gov/st-louis/opf.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgement as well as a substantive response to your reference request from RL-SL. We apologize for this inconvenience and appreciate your understanding and patience.
We hope this is helpful. Best of luck with your family research!