Last month, we were talking about the competent person role that is required by OSHA anytime an excavation is underway. This month, we will talk some about excavations themselves.
Remember that the Occupational Safety and Health Administration (OSHA) defines excavation for us at 29 CFR 1926.650: “any man-made cut, cavity, trench, or depression in an earth surface, formed by earth removal.” In case you are now wondering, a trench is an excavation (but an excavation is not necessarily a trench).
OSHA tells us that trench, “means a narrow excavation (in relation to its length) made below the surface of the ground. In general, the depth is greater than the width, but the width of a trench (measured at the bottom) is not greater than 15 feet.” So, presumably, once it is really wide, it’s nothing fancier than just a hole.
Now, we have to remember that Delaware is a so-called “non-plan state,” meaning workers at state and local agencies here are not covered by OSHA (if you are a reader from Maryland, North Carolina, Vermont, or one of the other states or territories with OSHA-approved State Plans, rest assured that in your state, OSHA most definitely applies to your local agency personnel, in accordance with your State Plans; but not in Delaware); it’s wierd.
But make no mistake, private sector personnel in Delaware are protected by OSHA and are subject to their regulations. When they are working on your projects, they are subject to OSHA regulation, even if you technically aren’t. And, thankfully, most Delaware local agencies recognize that OSHA standards and regulations are best practice and seek to follow them anyway. And, that’s what we’ll do here, because even at three or four feet deep, enough soil can cave in on your chest that your lungs won’t be able to move in and out, so let’s up our game here.
So, back to these holes in the ground. As local agencies, you and/or your contractors dig holes for all kinds of things, and not always with much advance notice. Think of water main breaks, sewer line back-ups, storm drain repairs, burying a councilperson**, and so on. Given the broad definition of “excavation,” just about any of your excavation work is going to trigger several requirements, including the so called competent person requirements (see our March 2024 e-newsletter article on that topic).
You should get out of the habit of reasoning away the need for certain safety requirements for excavations. Oh, it’s less than X feet, oh, it’s not technically a trench, oh…oy veh. Let’s first apply some common sense, particularly if we are excavating in unstable conditions, previously disturbed soils, wet soils, and so on. Technicalities are of small consequence when someone is killed in an excavation (39 fatalities in 2022).
So, let’s begin with egress. Don’t complicate this. OSHA is clear. If the excavation is a trench and at least four feet deep, a stairway, structural ramp, ladder, or other safe means (to get out of there and fast) is required with no more than 25’ of lateral travel. So, if your trench is 30’ long, the ladder can be in the middle and you’re good. If it is 55’ long, get two ladders. Don’t make this complicated. Now, all the ladder requirements apply, of course, but we will cover that in an article somewhere down the line.
If you can reasonably expect that the excavation may be oxygen deficient (<19.5% oxygen) or in excess of 20% of the lower flammable limit of the gases present, and it is four feet or greater in depth, you must test the atmosphere. Again, don’t get overly clever with this. Digging next to the fuel station that’s been there since 1923? Check the atmosphere. Excavating a pipe next to the landfill? Check the atmosphere. You get the point. These meters are relatively inexpensive and they are tools of the trade if you are going to be excavating. If you don’t own them, you can rent them. These hazardous atmospheric conditions also trigger the need to have safety harnesses, breathing apparatus, and other rescue equipment readily available, so make that part of your planning.
Next, if the excavation contains water or is accumulating water, and a lot of emergency repairs will, other precautions are required. In essense, everything else about excavation safety is mostly based on the notion that the trench is dry. There are some pretty common, fairly simple means to address accumulating water, so this should not be a big arguing point. If you are ankle deep in water in the excavation, you probably need greater controls, particularly if the sea is rising.
Let’s pause here and say that the competent person will be monitoring all these conditions and should have these things well in hand. But if you see that they are not, time to ask…who is the competent perons for this operation? And, all of this four feet, five feet stuff? If the competent person, during the required daily inspections, observes conditions less than these depths that present risk, he/she must require measures to mitigate the risk or remove the workers from the excavation.
Loose rock or soil or other materials and equipment that can fall or roll into the excavation must be kept back at least two feet from the edge. Simple as that. And if you’re unsure whether it’s all back 23 inches or 24 inches…move it back.
Now on to protective systems. Unless you are in stable rock (it’s Delaware; it is
highly unlikely) or in an excavation less than five feet that the competent person has determined to be adequate without it, a protective system is required. This gets very detailed, very quickly, and we won’t try to summarize it here. We strongly recommend that the competent person regularly review 29 CFR 1926.650 to ensure that all bases are covered. Of the many drivers, the soil type is the one we begin with. We are unlikely to encounter stable rock or even Type A soil (cohesive soil with an unconfined compressive strength of at least 1.5 ton/SF, among other requirements). In Delaware, we are far more likely to find Type B (cohesive or granularr soils with lesser strength) or Type C (even weaker and less stable). The competent person must characterize the type of soil because it drives decisions about the type and design of the protective system (shielding, shoring) and even affects your sloping and benching options.
There is, of course, the option of benching or “laying back” the material, but we almost never have the room for this or the space to temporarily store all that excavated material, so we’ll move right to physical support systems, shield systems, and the like. Here, too, there is an option for timber support systems and there are (very detailed) allowances for their use, but if you going this route, a design must be completed by a professional engineer and you can forget the use of things like plywood.
No, these days, you should really be considering professionally designed and constructed shield systems (mine boxes, trench boxes) and even then, you need to bear in mind that any such system has conditions it was designed for, and we must not exceed those conditions. Finally, these shields have to be cared for. Once they are damaged, gored, speared, bent, contorted, and so on, it is likely that they can no longer be certified. The system will include instruction as to how it can be moved, lifted, shifted, etc., and if you don’t follow those instructions, you may find that your expensive shield system is no longer useable.
If you are in the business of maintaining underground utilities like water and sewer lines, it is high time you recognized that your personnel are at least occasionally in circumstances where these requirements (or in the case of Delaware public agencies, best practices) kick in and your assigned competent person should ensure that the right protective equipment is on hand and ready to deploy when these emergencies aise. Regular training of personnel in the use and application of the equipment is important to instill a culture of safety.
Granted, the OSHA standards for excavations are a little complicated, but not so much that a competent person cannot read and understand them. To do so, the competent person should regularly review the standards (the standards themselves; not a summary or list of bullet points or even a brilliantly written e-newsletter article – 29 CFR 1926.650) and ask questions. Then, as is the case with most regulations, when it becomes unclear whether you “have to do” something, do two things. First, if you have to scratch your head that much, maybe just go ahead and do the thing that maybe, maybe you don’t have to do; err to the conservative when it comes to safety. Second, step away from the bureaucratic langauage of the standards and ask yourself, “what are the risks and how can we either eliminate them, reduce them, or mitigate them?” That may answer your question. If not, contact you local OSHA office and ask them – they won’t bite.
Any implied or explicit jesting aside, excavations of (almost) any depth can get you in trouble, particularly considering that public works excavations commonly occur in previously disturbed, wet, unstable soil immediately adjacent to moving traffic, in the dark, in the rain, while someone is insisting you restore service quickly. Take the time to be safe, insist that the competent person fully analyze the conditions, and get the right protective equipment in place to ensure that no one is in danger. Soil moves fast when the excavation sidewall is collapsing and you are not going to outrun or out climb it, so get a better plan than that, regardless of whether OSHA is the boss of you or not.
** Special note – no councilpersons or other elected officials were actually harmed in the writing of this article.
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