28 CFR § 551.4
Hair length
July 24, 2020
(a) The Warden may not restrict hair length if the inmate keeps it neat and clean.
(b) The Warden shall require an inmate with long hair to wear a cap or hair net when working in food service or where long hair could result in increased likelihood of work injury.
(c) The Warden shall make available to an inmate hair care services which comply with applicable health and sanitation requirements.
[44 FR 38252, June 29, 1979, as amended at 46 FR 59509, Dec. 4, 1981]