How would I find out if the WWII assignments of a great uncle, whose work in WWII was classified, has been declassified?

Question

We are learning our great uncle, Major Ray Arthur Nichols, who is buried at Arlington, was engaged in classified work during WWII. Wondering how we might find out if that work was ever declassified? We do know he was part of the OSS, and that he flew to China to help secure the release of the Doolittle flyers, who were POWs of the Japanese. Born in 1906; died in 1956. 
 Thank you! 
 J.

Textual Reference Branch, Archives II · Answer

JennyIngrid 
 Thank you for posting your request on History Hub! 
 We searched within the series Personnel Files of the Office of Strategic Services, 1942&ndash;ca. 1962 (entry A1 224) in the Records of the Office of Strategic Services (OSS) (Record Group 226) and located the file Nichols, Ray A., Maj - [Serial Number] O-301875 in box 559 of the series. These records have not been digitized, but they are open and available for researchers to access at the Textual Reference Branch at National Archives in College Park, MD (Archives II). You may email the Textual Reference staff at archives2reference@nara.gov for more information about this file. 
 We also searched the non-digitized Personal Name Index to the OSS records at Archives II, as well as the OSS index to the Director&rsquo;s Files (Microfilm Publication M1642), but we were unable to locate any entry for Ray A. Nichols in these indexes. 
 Next, we located the series Kandy, Kunming, London, Madrid, New York, Paris, Shanghai, Singapore, and Stockholm Field Station Files, 1941&ndash;1947 (entry A1 168) in Record Group 226, which contains some records related to the Doolittle flyers. The microfilmed Director&rsquo;s Files (M1642) mentioned above also include some references to the Doolittle flyers. Please email archives2reference@nara.gov for further assistance with these and similar non-digitized records. 
 We invite you to continue the conversation with community members on History Hub, but should you have follow up questions for the staff at Archives II, please email us at archives2reference@nara.gov so that we can assist you further. 
 We hope this is helpful for your research! 
 Sincerely, 
 Textual Reference Archives II Branch (RR2RR) 
 [RR2RR 24-23956-RS]