Public institutions of higher learner have a responsibility to make academic content (textbooks, A/V materials, etc.) accessible to students with disabilities.
While copyright law provides limited exceptions for reproduction and distribution of materials for "use by blind or other persons with disabilities" (the Chafee Amendment, 17 U.S.C. § 121), the Association of Research Libraries' Code of Best Practices in Fair Use for Academic and Research Libraries supports the reproduction of "material for use by disabled students, faculty, staff and other appropriate users" under fair use.
PRINCIPLE:
When fully accessible copies are not readily available from commercial sources, it is fair use for a library to (1) reproduce materials in its collection in accessible formats for the disabled upon request, and (2) retain those reproductions for use in meeting subsequent requests from qualified patrons.
-- ARL, Code of Best Practices in Fair Use for Academic and Research Libraries, p. 22