Md. Code, Pub. Util. § 12-130

(a) (1) This section applies to a primary contractor that: (i) performs the excavation duties for the duration of a ticket; (ii) initiates the notification to the one–call system to establish a ticket; (iii) is on site to supervise all activities and employees; and (iv) intends to utilize services or equipment of a temporary excavator. (2) For purposes of this section, a primary contractor does not include a private homeowner that intends to hire a temporary excavator. (b) A primary contractor: (1) shall: (i) notify the one–call system when a temporary excavator is to begin work under the ticket; (ii) inform the temporary excavator of the exact scope of work as detailed on the existing ticket; (iii) directly supervise the on–site activities of the temporary excavator; and (iv) assume all liability if damage should occur to an underground facility by any person named as a temporary excavator on the existing ticket; and (2) may name only one temporary excavator for the duration of the ticket. (c) (1) A temporary excavator may be: (i) a piece of rental equipment and its operator; (ii) an excavation contractor that is not an employee of the primary contractor; or (iii) an equipment operator that is not a direct employee of the primary contractor. (2) The designated temporary excavator shall notify the one–call system with the associated ticket number to verify that the excavator has been hired to work for the primary contractor.