EAST retentions are viewable in OCLC, Gold Rush, and for serials only, the Center for Research Libraries’ PAPR database.
For OCLC, consult the View Shared Print retention commitments to see how to search in the various services. Also, there is a google sheet add-on for checking a list of OCNs, though it does require an OCLC Metadata API key. OCLC cataloging subscribers may request keys at https://platform.worldcat.org/wskey/. Note that at least one member library’s holdings are no longer in OCLC.
Logins for Gold Rush are available to EAST members by contacting the EAST Program Team at info@eastlibraries.org.