Trench Safety Month is June! Trenching and excavation training should be provided to employees in order to comply with OSHA regulations and to learn about trenching hazards and how to reduce them.

1. The 8 Types of
Trenching and
Excavation
Hazards

2. Trenching and Excavation hazards continue to be a prominent cause of
worker injuries and fatalities in the United States. Between 2019 and
2021, 38 workers died due to trench collapses alone as cited in OSHA’s
Fatality Inspection Data. According to the U.S. Bureau of Labor’s 2020
Census of Fatal Occupational Injuries Table A-9, 19 workers employed in
construction suffered fatal injuries due to excavation and trench cave-ins
in 2020. These numbers should raise a red flag for employers and
employees and increase the need for safety awareness from trenching
hazards at construction sites.
What is a Trench?
A trench is an excavation (or hole in the ground) where the depth is
greater than the width.
One tried and tested method is to ensure workers receive adequate
training on OSHA regulations and safe work practices in accordance with
Federal OSHA Regulations 29 CFR 1926 Subpart P which provides
guidance on specific excavation requirements and the use of protective
systems for excavation and trenches.

3. Our OSHA Competent Person for Excavation, Trenching, and Shoring Training course has been developed by
OSHA-authorized trainers and provides detailed guidance on soil classification, protective systems, and safe
work practices.
Trenching and Excavation Hazards
Let’s discuss the eight commonly encountered trenching and excavation hazards that cause worker injury and
death in the construction industry.
1. Trench Collapses or Cave-Ins
A trench collapse or a cave-in occurs when the walls of the trench or excavation site collapse inwards due to
instability or improper use of safety techniques such as sloping or benching the sides of the trench, shoring or
supporting the sides of the excavation, or placing a shield between the sides of the excavation/trench and the
work area.
Some of the most common reasons for trench or excavation collapses are attributed to unstable soil, vibrations
due to machinery being used nearby, vibrations from heavy traffic passing close to the trench, flooding, heavy
rainfall, and excessive pressure placed on the edge of a trench.

4. 2. Falling Hazard
Workers working in trenches and excavations are exposed to the hazard of falling into the trench or
excavation. This is more common when workers must cross over excavations to get to the other side. Putting-
up safety signs, installing guardrails for walkways that are 6 feet or higher from the bottom of the trench or
the lower level, and/or placing barriers around the edges of trenches and excavation sites can reduce the risk
of workers falling inside the trenches and sustaining injuries.
3. Struck-By Hazard
This happens when objects, tools, or other equipment falls on workers working inside the trench or excavation.
This could be due to the tools being placed too close to the edge of the trench resulting in them slipping and
falling inside the trench causing injury to workers.
By placing barriers at the edge of the trench and excavation areas, workers’ risk from struck-by hazards can be
greatly reduced as this would stop tools and equipment from accidentally falling inside trenches.
4. Superimposed Load or Surcharge Hazard
When excess loads or weight are placed at the top of a trench, there is a risk of such vertical loads (e.g.,
excavated soils and other materials, vehicles, or equipment) resulting in reducing the stability of a trench or
excavation area. This excessive pressure on the soil could cause the trench edge to collapse resulting in the
machine or the excavated soil falling inside the trench and risking serious injury to workers. Therefore, when
the stability of the trench is reduced it can cause the dual hazards of cave-ins and falling loads.

5. 5. Atmospheric Hazards
Trenches and excavation sites are prone to atmospheric hazards due to the worksite being underground.
Workers can be exposed to toxic atmospheres (due to the presence of toxic gases or chemicals), or suffer
from asphyxiation caused by a shortage of, or lack of, oxygen due to a cave-in or the nature of the confined
space (meaning the trench or excavation site) they are working in.
According to OSHA’s Excavations Standard, 29 CFR 1926 Subpart P, a competent person must undertake
daily inspections to test trenches and excavations for hazardous atmospheres. These inspections should be
done before work begins and as necessary throughout the shift. Furthermore, employers must also
provide workers with adequate respiratory protection or ventilation in trenches or excavations that
contain less than 19.5 percent oxygen (an oxygen-deficient atmosphere) and where a hazardous
atmosphere is detected.
6. Hazards Caused by Mobile Equipment and Machinery
When workers operate mobile equipment or machinery close to trenches and excavations, the judgment of
when to stop before reaching the edge of the trench or excavation can sometimes be incorrect. Therefore,
using stop logs and barricades can help reduce the hazard of equipment being too close to the edge. Using a
communication system such as hand signals between equipment operators and the ground workers is also a
good safe workplace practice that can be adopted at excavation sites.

6. 7. Electrical Hazards
Often working underground results in workers being exposed to underground electrical wiring, underground
power lines, or other underground utilities such as telephone lines and water. This is a cause of concern as
workers could be exposed to electrical hazards such as shocks and electrocutions as well as fires and explosions.
To safeguard workers, employers should contact the utility companies and the location of the underground
utility and put in barriers to avoid the area when working in the trench or get the water supply or power shut
down before work begins in trenches.
8. Drowning and Flooding Hazards
Working in trenches and excavations exposes workers to the hazards of drowning and flooding. Flooding can
occur due to ruptured water pipes in the excavated area or even from heavy rainfall or thunderstorms.
Employers should ensure the utility underground location is identified in advance, and barriers placed around it
with relevant safety signage when work is being carried out. Furthermore, precautions such as harnesses and
lifelines, shielding systems, and other water removal measures can be utilized to reduce water accumulation in
excavation sites. These must be supervised by a competent person. In instances of rainstorms, the excavation
site should be cleared of workers and a competent person must inspect the site before work begins again to
ensure that the trench is safe from the danger of cave-ins or re-flooding.

7. OSHA-Complaint Safety Training
To protect workers from trenching and excavation hazards, employers must train workers to recognize
trenching hazards, understand the dangers to safety and health of exposure to such hazards, and ways to
minimize such hazards. As competent persons play a critical role in ensuring worker protection when working
in trenches and excavation sites, employers must train workers to be competent persons when working in
excavations and trenches. Our OSHA Competent Person For Excavation, Trenching, and Shoring Training
course will provide detailed guidance and protect workers and reduce employer liabilities and work stoppages
due to accidents and injuries.
June is Trench Safety Month!
Support and contribute to the safety of workers by acting today!
Protect Workers’ Health and Safety from Trenching Hazards.
Enroll your employees in our OSHA Competent Person for Excavation, Trenching, and
Shoring Training course.
Call us for details about in-person on-site group training, virtual instructor-led training,
and employer group discounts.

8. 1-866-429-6742
https://hazwoper-osha.com/
info@HAZWOPER-OSHA.com
Contact US!