17 U.S.C. § 121. Limitations on exclusive rights: Reproduction for blind or other people with disabilities
"(a) Notwithstanding the provisions of section 106, it is not an infringement of copyright for an authorized entity to reproduce or to distribute copies or phonorecords of a previously published, nondramatic literary work if such copies or phonorecords are reproduced or distributed in specialized formats exclusively for use by blind or other persons with disabilities. ..."
Other useful information:
Maria Scheid, "Copyright and Accessibility," Copyright Corner (blog), Aug. 28, 2015.
Karyn A. Temple, "The Marrakesh Treaty Implementation Act," Copyright: Creativity at Work (blog), Oct. 10, 2018.