The plaintiffs appeal from the district court’s dismissal of their lawsuit alleging that the defendants violated the plaintiffs’ Eighth Amendment rights while the plaintiffs were incarcerated at the Bastrop Federal Correctional Institution. This court reviews a dismissal under Rule 12(b)(6) of the Federal Rules of Civil Procedure de novo. Edwards v. Johnson, 209 F.3d 772, 776 (5th Cir. 2000).

In their first issue, the plaintiffs challenge the district court’s dismissal based upon the general Rule 12(b)(6) standard but fail to adequately brief their argument. Accordingly, that issue is waived. See Yohey v. Collins, 985 F.2d 222, 224-25 (5th Cir. 1993); Fed. R.APP. P. 28(a)(9).

The plaintiffs also contend that the district court’s dismissal for failure to exhaust administrative remedies was erroneous because there was no evidence in the record that any administrative remedies existed, other than the remedies that the plaintiffs pursued. As noted in district court, the Bureau of Prisons has established an administrative remedy program. 28 C.F.R. §§ 542.13-542.15; see also Lundy v. Osborn, 555 F.2d 534, 534-35 (5th Cir. 1977). For the purpose of meeting the exhaustion requirement set forth at 42 U.S.C. § 1997e(a), it is the plaintiffs who must allege exhaustion with sufficient specificity. See Underwood v. Wilson, 151 F.3d 292, 294, 296 (5th Cir. 1998); see also Days v. Johnson, 322 F.3d 863, 866 (5th Cir. 2003) (“Since the amendment of § 1997e, this Court has taken a strict approach to the exhaustion requirement.”). Accordingly, the plaintiffs’ argument lacks merit.

*768 As the plaintiffs have failed to challenge the district court’s dismissal on any other basis, the district court’s judgment is AFFIRMED.