D.C. Code § 34-2706: Damage caused by excavation or demolition.

(a)

Except as provided in subsection (b) of this section, each person responsible for any excavation or demolition operation which results in damage to an underground facility shall, immediately upon discovery of such damage, notify the operator of such facility of the location and the nature of the damage, and shall allow the operator reasonable time to accomplish necessary repairs before continuing the excavation or demolition in the immediate area of the damaged facility.

(b)

Each person responsible for any excavation or demolition operation that results in damage to an underground facility, permitting the escape of any flammable, toxic, or corrosive gas or liquid shall, immediately upon discovery of such damage, notify the utility operator, 911, and any other agency identified by the Mayor and take any other action which may be reasonably necessary to protect persons and property.