28 C.F.R. § 549.72

We will not charge a fee for:

(a) Health care services based on staff referrals;

(b) Staff-approved follow-up treatment for a chronic condition;

(c) Preventive health care services;

(d) Emergency services;

(e) Prenatal care;

(f) Diagnosis or treatment of chronic infectious diseases;

(g) Mental health care; or

(h) Substance abuse treatment.