Stop the machine and leave it where it is. What happens next depends entirely on what you hit: gas and electric are a 911 call before they are anybody's repair job, water and sewer are a call to the system that owns the line, and fiber is expensive rather than dangerous. Nothing gets backfilled, moved or cleaned up until the owner of that line has seen it.
Gas
Everyone off the site and upwind, on foot. No engines started, no engines shut off, no phones used standing over it, nothing that makes a spark, and do not try to crimp, plug or cover the leak. Get well clear, then call 911 and the gas utility. If the machine is still in contact with the line, leave it. A running excavator is an ignition source and so is the starter motor you would use to move it.
Electric
If the machine is in contact with an energized line, the safest place is usually inside the cab. Stay there, keep everybody else back, and call 911 and the utility. The ground around a machine in contact can be energized well beyond the machine itself, which is what gets bystanders hurt. If fire forces you out, jump clear so you are never touching the machine and the ground at the same time, land with your feet together, and shuffle away in small steps without lifting a foot.
Water
Call the water system that owns the main. A struck service or main moves a lot of water fast, and the real damage is often not the pipe: it is the road base, the trench walls and whatever is downhill. If you are not sure who supplies that town, we publish it: who supplies water in New Jersey, town by town. Nobody should be standing in a trench with water coming in, and a saturated trench wall is a cave-in waiting to happen even in ground that was solid an hour ago.
Sewer
Call the municipality or the utilities authority on the bill. A broken lateral is a contained problem. A broken main is a public health problem, and it stops being yours to manage the moment you report it.
Fiber and telecom
No immediate danger, and that is exactly why people mishandle it. Do not pull it, straighten it, tape it or move it out of the way, and do not let anybody splice it who was not sent by the owner. Call the number on the pedestal or the warning tape and report it straight away. Every minute a cut runs is service somebody is paying for, and the claim that follows is built on how fast it was reported and what the site looked like when it happened.
Document it before anything moves
The claim is decided by what the ground looked like in the first ten minutes, and the only person standing there is you.
Photograph the paint and the flags with the damage in the same frame, wide enough to show the relationship between them. Photograph the depth, with a tape or a rod in shot. Photograph the line itself and the equipment position. Write down the One Call ticket number, the date the marks went down, and the time of the strike. If the marks were absent, wrong or badly offset, that is the whole defense, and it only exists if it was photographed before the repair crew changed the scene.
The rule the argument usually turns on is the tolerance zone: under New Jersey's One Call rules, mechanized equipment may not be operated within two feet horizontally of the outside wall of a marked facility until the facility has been exposed by hand. We wrote about why that gets measured on every job in the 24 inch rule. If the machine was outside that zone and the line was not, the marks are the problem rather than the operator.
What we do, and what we do not
We do not repair gas and we do not repair energized electric. Those belong to the utility that owns them, always, and anybody who offers otherwise on the phone is telling you something useful about themselves.
Once the owner has made it safe, the excavation side is ours: water and sewer repairs, conduit and duct, drainage, road and shoulder restoration, and 24/7 response on fiber and utility strikes. We show up with the machine, the shoring and the crew to open it properly rather than widen a hole somebody started in a hurry. The repair dig itself still runs under New Jersey's emergency provisions, which are a defined notification process rather than an exemption from the markout, and we handle that call.
If you are standing over one right now and the line is safe, call us at any hour. If it is gas or electric, call 911 first and us second.