Final answer:
In the event of a gas line damage during excavation, both 911 and the gas company should be promptly notified for immediate response and expert handling of the situation.
Step-by-step explanation:
If a gas line has been damaged while excavating, it is crucial to notify the appropriate emergency services immediately for the safety and wellbeing of everyone in the vicinity. The correct entities to notify would be both 911 and the gas company. By calling 911, you will alert the local emergency services who can swiftly respond to the hazard. Notifying the gas company is also essential as they have the expertise and authority to control the gas supply, assess the damage, and repair the gas line. It is important to evacuate the area and ensure that no one uses an open flame or anything that could ignite the gas.