Safety Before We Dig

2/22/2021

It is truly amazing how fast time flies. I was thinking of an event that seemed like it happened a few years ago, but it was closer to 25 years. But the incident remains fresh in my mind.  I was working at a naval facility in Southern California. It was lunch time so a bunch of us went to pick up a quick bite to eat and when we got back to the base, we saw groups of people hanging around, outside the administrative building while fire trucks surrounded the area and firemen where dressed in full gear. Nobody looked to be in much of a panic and since we had time, we thought we would see what was going on. We noticed this one guy sitting on a fire hydrant looking very depressed. I asked him what was going on and he replied that he was operating his back hoe – just like he was told to do – and to stop at four feet, because that’s where the original drawings of the building (typically referred to as “as-builts”) indicated that a gas line was installed. He said that when he reached 2 feet, he hit the line, causing it to rupture. And because natural gas is a very flammable material (having a lower explosive limit at 4%), precautions were enforced, whereby the building occupants had to be evacuated while emergency response personnel were contacted.

This incident could have very easily been avoided if only the proper steps were followed. And while the equipment operator was only following instructions, I was never able to find out if his boss/company was following a formal protocol or if someone in the chain-of-command just ignored the mandatory requirements to first pothole to a depth of 5 feet prior to using heavy equipment.  As a result, a gas line was breached and if an open flame – such as a lit cigarette or a spark from a nearby activity or vehicle – was close enough, a disaster could have occurred. Trying to guess what the resulting implications could have been would only be a conjecture (whether it was injured persons or damaged equipment/materials/property). But any mention of a natural gas leak resulting in an unfortunate event, would have surely made the 5 o’clock news.   

By using manual methods, such as hand auguring, to first penetrate the ground surface, we can avoid a serious incident – such as breaching a gas line or an electrical conductor.  And while “as-built” drawing may be available, often these prints are not exact. And the reasons why these drawings wind up being less-than-accurate, are too numerous to list. Sometimes the inaccuracy is due to poor communications between the planners or possibly someone decided that installing a utility line to its proper depth was too much trouble (time and money) while believing one would never know (at least in their lifetime!).

When it comes to excavation safety, OSHA regulations for excavation safety; 29 CFR 1926, Subpart P (Sections 650-652), mainly focuses on worker protection during exaction work. For instance, the OSHA excavation regulation discusses measures to control cave-ins, addressing soil stability and methods of proper sloping and using mechanical devices to protect workers while in an excavation.  29 CFR 1926, Subpart P also specifies the requirements for safe means of egress and the use of a competent person to assess the safety of an excavation prior to entry. 

However, OSHA does mandate that that certain precautions associated with underground utility lines need to be established prior to penetrating the ground surface. Specifically, 29 CFR 1926.651(b) addresses underground installations.

“The estimated location of utility installations, such as sewer, telephone, fuel, electric, water lines, or any other underground installations that reasonably may be expected to be encountered during excavation work, shall be determined prior to opening an excavation.

“Utility companies or owners shall be contacted within established or customary local response times, advised of the proposed work, and asked to establish the location of the utility underground installations prior to the start of actual excavation. When utility companies or owners cannot respond to a request to locate underground utility installations within 24 hours (unless a longer period is required by state or local law), or cannot establish the exact location of these installations, the employer may proceed, provided the employer does so with caution, and provided detection equipment or other acceptable means to locate utility installations are used.

“When excavation operations approach the estimated location of underground installations, the exact location of the installations shall be determined by safe and acceptable means.

“While the excavation is open, underground installations shall be protected, supported or removed as necessary to safeguard employees.”

And while the OSHA regulation does NOT address specific safety practices, OSHA has provided a means to address concerns brought up by companies or individuals where it is felt that the actual regulation does specify the appropriate controls. These are known as OSHA “Letters of Interpretation.” In the case of locating underground utilities (as stated above), an inquiry was made as to “what constitutes an acceptable method of uncovering underground utility lines, and further, would the use of hydro-vacuum excavation be acceptable under the standard?”

OSHA responded in one such letter of Interpretation (dated 10/23/2003 and reviewed on 11/22/2017).

“When utility companies or owners cannot respond to a request to locate underground utility installations within 24 hours * * * (sic) or cannot establish the exact location of these installations, the employer may proceed, provided the employer does so with caution, and provided detection equipment or other acceptable means to locate utility installations are used.
(Emphasis added.).”

Yet, the terms, “other acceptable means” and “safe acceptable means,” were never defined by OSHA. This prompted considerable discussion and research by OSHA and those private entities that wished to contribute their opinions on the matter. The result was that OSHA has since recognized the use of hand tools and hydro vacuum excavation equipment (when used with minimum water and suction pressure) would be “acceptable.”

OSHA concludes that “We are not suggesting that these are the only devices that would be “acceptable means” under the standard. Industry stakeholders have informed us that there are other types of special excavation equipment designed for safely locating utilities as well.”

Many municipalities and government agencies have realized that a more definitive approach needs to be applied when excavating in locations where underground utilities may be present. Many agencies require that potholing (the practice of manual digging -using a shovel for instance – one or more test holes to find out the exact location of an underground utility) needs to be performed anywhere within 5 feet of a suspected underground line.

The point is, that by merely following a regulation – OSHA or otherwise – does not guarantee that work will be performed without compromising the safety and health of a work crew as well as the immediate community.  In addition, as illustrated through the story of the unfortunate backhoe operator, we can never assume that even when information is documented, that the task should proceed without asking some fundamental “what-if” questions.

A wonderful fact to reflect upon, that every human creature is constituted to be that profound secret and mystery to every other

Charles Dickens