D.C. Code § 8-634.04
(a) Upon a determination of a threat or an actual release of a hazardous substance that is a threat to the public health, welfare, or the environment, for the purpose of inspection and obtaining samples, the Mayor may enter at reasonable times, and issue orders as necessary to gain entry to, a facility, establishment, or other property if:
June 13, 2001, D.C. Law 13-312, § 404
as added Apr. 8, 2011, D.C. Law 18-369, § 2(k), 58 DCR 996
For temporary (90 day) addition, see § 2(k) of Brownfield Revitalization Emergency Amendment Act of 2010 (D.C. Act 18-667, December 28, 2010, 58 DCR 95).