Five Most Prevalent Myths About OSHA's Excavation Standard

Common Misconceptions About Actual OSHA Requirements

June 1, 2016 -  My favorite class to teach is the Excavation Competent Person Training Course. Perhaps that is because it is one of the more relatively complex topic in the federal OSHA standard, and a lot of people seem to misunderstand what is (and is not) required to comply with the regulations. So I thought I’d address the top five most prevalent myths and misconceptions that seem to pop up repeatedly during the classes that I have taught, as well as during site inspections and interviews conducted as an expert witness in lawsuits involving trenching and excavation fatalities.


MYTH #1“A protective system is not required to be utilized in an excavation unless it is at least five (5) feet deep.”

FALSE. Many times I have heard people say that OSHA’s excavation standard only requires employers to utilize some sort of protective system (trench box, shoring, sloping or benching . . .) whenever a worker is going to enter an excavation five feet or deeper (unless made in stable rock). But what OSHA standard 1926.652(a)(ii) actually requires is that a protective system be utilized in all excavations, even those less than five feet deep, except whenan examination of the ground by a competent person provides no indication of a potential cave-in”.

Many of you have probably excavated at sites with dry fine sand that actually flows as you are digging, or perhaps you’ve had the headache of digging a trench in soupy mud. In those cases, cave-ins can occur in trenches much less than five feet deep. So regardless of the fact that you might not be digging to five feet or more in depth, the competent person for the excavation site must still evaluate the excavation area and then determine whether or not some sort of protective system is needed to protect workers in that excavation.


MYTH #2“Our employees are automatically protected from cave-ins in a trench whenever we install a trench box.” 

FALSE. Merely installing a trench box (or shield system, as OSHA calls them) in your excavation does not automatically mean your employees are adequately protected. That is because all trench boxes are not created equally. In fact, I am shocked by how many people utilize a trench box for protection of workers in a trench without having any idea whether or not that trench box is actually strong enough to withstand the weight of a collapsing trench wall.

OSHA standard 1926.652(g)(1)(i) states that shield systems “shall not be subjected to loads exceeding those which the system was designed to withstand”. While the trench box you are using may look strong, one must refer to the manufacturer’s tabulated data for the particular brand and model of trench box being utilized (as well as its configuration) to determine how deep it can be used. And that, in turn, depends on the type of soil you are digging in, as demonstrated in the sample table below.  


trench box tabulated data chart


Using a trench box in an excavation that is deeper than it is rated for in a particular type of soil can cause the box to become overloaded and collapse.

One more reason some workers still get killed or injured when using a standard trench box is because, while they offer protection from cave-ins on the sides of the trench, they do not necessarily protect from cave-ins at the ends of the trench. In those situations where soil could slid or collapse into one or both ends of a trench box, some form of approved protection must also be provided to protect workers. This could include, but is not limited to, the installation of approved end plates, sloping of the soil per the OSHA sloping charts, or the use of specially designed trench boxes that incorporate end protection into their design.


MYTH #3“The competent person must conduct one inspection of our work-site before we start work, and then we are good for the day.”

FALSE.  A lot of people probably believe the competent person must only make one inspection of the excavation site each morning before work begins because OSHA standard 1926.651(k)(1) starts off by saying “Daily inspections of excavations, the adjacent areas, and protective systems shall be made by a competent person for evidence of a situation that could result in possible cave-ins, indications of failure of protective systems, hazardous atmospheres, or other hazardous conditions.” But the standard also says that “an inspection shall be conducted by the competent person prior to the start of work and as needed throughout the shift”. The standard then goes on to say that “inspections shall also be made after every rainstorm or other hazard increasing occurrence”.

So as you can see above, there are many cases where additional inspections by the competent person might be needed as work progresses throughout the day.


MYTH #4 – “OSHA requires a walkway be installed over all excavations over which employees are allowed to cross.”

FALSE. This belief is understandable because the OSHA standard that addresses this situation [1926.65(l)] actually says that “walkways shall be provided where employees or equipment are required or permitted to cross over excavations”. But what if a worker wants to cross over a trench that is only three inches wide?  Do you think that a walkway is really necessary?  And what if it only six inches wide? Thankfully, this issue is cleared up by federal OSHA in one of their letters of interpretation. In that letter, OSHA states that they consider crossing narrow trenches 30 inches or less in width to be a de minimis condition. Therefore, they go on to say, walkways or bridges must be provided when employees or equipment are required or permitted to cross over excavations only when the excavation is wider than 30 inches at the top.

So while you can certainly provide walkways for narrower trenches, at least now you know where OSHA draws the line.


MYTH #5 – “OSHA regulates excavations as permit-required confined spaces.”

False. The scope and application section [1926.1201(b)(1)] of the new Confined Spaces in Construction standard specifically exclude excavations from coverage by the confined space standard. However, section 1926.651(g) of the OSHA excavation standard still requires employers to take certain precautions in certain excavations where there is a potential for a hazardous atmosphere.

Read more about this particular topic in a previous blog post (click here).


So there is my overview of the top five most common myths and misconceptions about the OSHA excavation standard that I hear most often. And I could easily discuss five or ten more of them, but I will save those for possible use in future posts. And keep in mind that by discussing these topics here, I am not discouraging anybody from going above and beyond what is required by federal OSHA; my goal here is strictly to clear the air about what is (and is not) actually required by that agency.

Do you have any comment or experience you’d like to share about the five issues discussed in this post?  Or perhaps you have a question? If so, please post them in the COMMENTS section for this particular blog. And as always, Please Share this Blog post with others in your Network who might benefit from this information. 



Curtis Chambers is a Certified Safety Professional (CSP) and holds a Master of Science degree in Occupational Safety and Health. He has held numerous leadership positions managing and evaluating health and safety programs and providing training on workplace safety and health topics at various public organizations and private corporations. Mr. Chambers is currently the President of OSHA Training Services Inc. Visit their website at  
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