What must an excavator do to protect underground pipelines from excavation-related damage?

Prior to and during excavation activity, the excavator must: (a) Use an available one-call system before excavating to notify operators of underground pipeline facilities of the timing and location of the intended excavation; (b) If underground pipelines exist in the area, wait for the pipeline operator to arrive at the excavation site and establish and mark the location of its underground pipeline facilities before excavating; (c) Excavate with proper regard for the marked location of pipelines an operator has established by taking all practicable steps to prevent excavation damage to the pipeline; (d) Make additional use of one-call as necessary to obtain locating and marking before excavating to ensure that underground pipelines are not damaged by excavation.