How many trench dangers can you see? #HazardSpotting

| May 16, 2013

#HazardSpotting is a community safety initiative to help raise awareness about dangerous workplace safety violations. Our readers submit photos, and we write a post with special guest insight from featured safety experts. This week Robert L. Carlson comments on a photo taken of a construction trench by a MySafetySign employee.

Let’s be clear: April showers don’t just bring May flowers. They also bring annual flooding, mudslides, and ground collapses. At MySafetySign, we hate to dampen everyone’s spring spirits, but we also believe in putting safety first. That’s why one of our coworkers snapped the photo below on his way to work last week. It’s been a particularly soggy spring in New York, and the day of this photo had brought continuous drizzle all morning long. No wonder the construction worker on this ladder leapt out of the trench when he saw the camera—he knew perfectly well the dangerous conditions he had put himself in.

hazard spotting trench

Trench Support

Where to begin with the risks in play here? Even in dry weather, OSHA requires any trench deeper than five feet to be shored for support. That’s because the majority of trench collapses actually happen in trenches less than 12 feet deep. A shallow hole can easily give way due to previously disturbed soil, vibrations of the earth triggered by passing vehicles, or an unsafe distance between the spoil pile and lip of the trench.  And no matter how shallow the trench, the potential for injury is extreme: besides the risk of broken arms or legs, collapses can cut off workers’ oxygen supply, leading to asphyxiation, inhalation of toxic fumes, suffocation, and death. Adding a supportive trench box helps allay many of these risks. In this photo, we can see a feeble attempt to brace two sides of the trench, but workers are still exposed to the unpredictability of wet, unstable earth on either side.

Ladder Lean

Meanwhile, the trench is just wide enough to fit a ladder at the slightest tilt. OSHA stipulates that ladders lean at a 4:1 ratio—technically 75 ½ degrees. We don’t need to use our phone’s protractor app to be skeptical about this ladder’s lean. (And yes, there are several free protractor apps to choose from.) An unstable ladder makes workers liable to slip and fall—in the pictured trench, a tumble would send them right into a quickly-rising river of mud.

Cave-in Hazard

So what makes rainfall so particularly dangerous to trench projects? According to safety expert Robert L. Carlson wet pits are extreme cave-in hazards. “You can get trapped even if only your lower legs are stuck, and you can suffocate even if your head and arms are above the caved-in material,” Carlson says.

The trench itself looks like it was badly constructed, according to Carlson. “They’ve got a sidewall board, and upright boards behind it (shims?) and crossbracing, but there’s all this mud plastered to the sideboard on the inside of the pit. That’s enough to slide off and trap a worker, too.”

Air Testing and Utility Lines

Although you can’t tell from the picture, you have to wonder if the workers took other necessary precautions. Did they test the air quality, since the pit is over 4′ deep? Did they call the 800 number to make sure there weren’t buried utility lines? In addition to utility infrastructure, Carlson says, “They should notice if there was any soil or perched-groundwater seepage of contamination into the pit from any neighboring businesses like gas stations, print shops, machine shops, auto body places, etc. (current or former). So many times they have blinders on and don’t bother, even though it’s mandatory.”

Water Hazard

Work crews often dismiss the risks if they see little chance of full-body suffocation, but they’re choosing to work in direct violation of OSHA standard 1926.651(h)(1): “Employees shall not work in excavations in which there is accumulated water, or in excavations in which water is accumulating, unless adequate precautions have been taken to protect employees.” Those precautions may vary depending on the circumstances, but they can include special structural support or shield systems, pumping out water to control accumulation, or using a safety harness and lifeline.

A work crew should also know when to simply stay out of the trench for a day. The below photo is what a nearby trench looked like the day after the first picture. We think it was a good idea for the trench worker to scurry out of the trench when he did—and hopefully next time he’ll know to stay out.

flooded trench hazard spotting

More about #HazardSpotting

Think you’ve seen an unsafe work condition? Whether it’s construction, manufacturing, or food safety, we’ll investigate the hazard. Snap a picture and share your story with us by sending an email to the editor at Krissa (at) We’ll write a post and consult a safety expert. Did we miss anything? Comment below.

Thanks to Bob Carlson, our featured safety expert. Mr. Carlson worked in the electronics industry in Silicon Valley before there were any relevant regulations, and saw firsthand the lax procedures for hazardous waste disposal extant at the time. He later worked for Greenpeace in San Francisco, then as a state hazardous waste inspector in St. Louis. Since then, as a private consultant, he’s conducted many hundreds of safety and environmental cleanup classes, a similar number of property inspections, and has provided expert witness testimony in liability cases involving contamination, for over twenty years. He holds a B.S. in Earth Sciences, and completed six years of university studies. You can visit his blog, Hazard Hot Sheet, for more information.

Category: #HazardSpotting

; ;