OPINION

Roy Duane Turner pleaded guilty to involvement in a conspiracy to manufacture methamphetamine, in violation of 21 U.S.C. §§ 841(a), 846 (2000), and use of a firearm in a drug crime, in violation of 18 U.S.C. § 924(c) (2000). The district court sentenced Turner to a total of 228 months incarceration, four years of supervised release, and ordered Turner to pay a special assessment and a restitution fee. Turner timely appealed, asserting the district court erred in two sentencing determinations related to his involvement in a drug conspiracy.

First, Turner asserts the district court erred in calculating the drug quantity for which he was liable. We review this claim for clear error. United States v. D’Anjou, 16 F.3d 604, 614 (4th Cir.1994). The district court based its determination on competent evidence. United States v. Randall, 171 F.3d 195, 211 (4th Cir.1999). Thus, Turner’s claim is meritless.

Second, Turner asserts the district court erred in enhancing his sentence un[*112] der U.S. Sentencing Guidelines Manual § 2D1.1(b)(5)(C) (2001), based on its determination that Turner exposed his minor children to a substantial risk of harm by manufacturing drugs in their residence. In reviewing the district court’s findings, we review factual determinations for clear error and legal questions de novo; mixed questions of law and fact are reviewed under a standard that gives due deference to the district court. United States v. Nale, 101 F.3d 1000, 1003 (4th Cir.1996). Because Turner stored and used dangerous manufacturing materials in his residence, the enhancement was properly applied. USSG § 2D1.1(b)(5)(C), comment. (n.20).

Accordingly, we affirm Turner’s convictions and sentence. We dispense with oral argument because the facts and legal contentions are adequately presented in the materials before the court and argument would not aid in the decisional process.

AFFIRMED.