At 2,700 lbs., a Volkswagen Beetle might be one of the lightest cars on the road. But you still wouldn't want one falling on your head.

The same theory applies to a cubic yard of soil, which also can weigh about 2,700 lbs. If you spend any time around that much excavated soil in a trench, the threat of being crushed or swallowed up by a ton or two of dirt should give any Hardhat cause for a pause before going in a ditch.

Each year, about 40 U.S. construction workers are killed in trenches. In addition, the fatality rate for excavation work is 112 percent higher than the rate for general construction.

The key to prevention, said OSHA's Jim Boom, "is the employer's leadership and commitment to a good safety and health program."

He said a crucial player in excavation safety is the company's designated "competent person." OSHA defines a competent person as one who is capable of identifying existing and predictable hazards or working conditions that are hazardous, unsanitary, or dangerous to employees, and who also has authorization to take prompt corrective measures to eliminate or control these hazards and conditions.

A designated person who is unfamiliar with the excavation requirements, who is unable to recognize hazards, or who doesn't have the authority to make corrective measures may miss a life-threatening condition.

At a minimum, OSHA said companies and workers should remember the three S's - sloping, shoring, or shielding - when planning an excavation.

OSHA's excavation standard requires employers to provide sloping (or benching), shoring, or shielding to protect employees in excavations five feet or more in depth. The only exception is for a trench dug in stable rock, where there is no loose soil or likelihood of a cave-in. Excavations less than five feet deep need not be protected unless a competent person has determined there is a cave-in hazard.

Here are a few other points to ponder, according to the Center to Protect Workers' Rights:

• Keep the spoil pile two feet or more from the edge of the trench.
• Prevent materials, rocks, or soil from falling into the trench; use barriers, if needed.
• A competent person should test the air as often as needed to make sure it is safe.
• If a trench caves in, call 911. Help your co-workers from outside the
  trench, if you can.
• You must have a way to get out, like a ladder (within 25 feet of you), if the trench is four feet deep or more.

Boom pointed out, that the world weightlifting record for the "clean and jerk" is 573 lbs by Russian Andrey Chererkin.

"One cubic yard of soil weighs nearly five times the world weightlifting records, Boom said. "Could you push back 500 pounds of soil with your arms or legs or, more importantly, could you breathe or even survive under the weight?

"Plain old dirt is so heavy that when you get caught under it, you do not have the strength to move or breathe as the dirt presses against your chest. Think about it! That's why trenching work needs special protective systems - so workers can go home safe and healthy at the end of the day."