California Department of Public Health

Occupational Health Branch

FATALITY ASSESSMENT AND CONTROL EVALUATION PROGRAM 

(CA/FACE) 

A heavy equipment operator dies when he was struck by an excavator

bucket that detached from a quick coupler

Case Report: 20CA001

SUMMARY

A heavy equipment operator died after being struck by an excavation bucket that became 

detached from the quick coupling device attached to the end of a boom. The job was located at a 

construction site for new homes. The victim was operating an excavator and digging trenches for 

the sewer system. After removing a few loads of dirt from a trench, the decedent swung the 

boom over to the side of the trench and exited the cab, leaving the boom elevated. As the victim 

approached the bucket and positioned himself under it, the bucket detached from the quick 

coupler and fell to the ground, striking him. The CA/FACE investigator determined that, in order 

to prevent future incidents, employers should ensure that operators of excavators with quick 

coupling devices: 

• Always lower the bucket to the ground before exiting the cab. 

• Never walk/traverse beneath an excavator boom swing radius or elevated load. 

In addition, employers should:

• Train hydraulic excavator operators in the proper procedures for engaging excavation 

attachments and incorporate these procedures into the company’s safety and health 

program. 

INTRODUCTION

On Wednesday, June 10, 2020, at approximately 7:15 a.m., a 21-year-old heavy equipment 

operator suffered fatal injuries when he was struck by an excavation bucket that detached from 

the quick coupler holding it onto the boom of the excavator. The CA/FACE investigator received 

notification of this incident on June 16, 2020, from the Cal/OSHA Weekly Fatality Report. On 

August 6, 2020, contact was made with the employer of the victim. On September 25, 2020, the 

CA/FACE investigator traveled to the location where the incident occurred and interviewed the 

victim’s supervisor/trainer, other operators, and the owner of the company. Photos of the 

equipment involved were taken. The county coroner, fire department, and sheriff’s department 

reports of the incident were obtained and reviewed.
2 

EMPLOYER

The employer of the victim was a general engineering contractor that specialized in water, 

sewer, and storm drain installation. The employer had been in business for 22 years and had 

approximately ten employees, but the number varied depending on the workload. There were 

two employees at the worksite at the time of the incident, one of whom was the supervisor.

WRITTEN SAFETY PROGRAMS AND TRAINING

The employer had a written injury and illness prevention program (IIPP) with all the required 

elements. Safety meetings were held weekly at the job site and were documented. Periodic 

training was also provided on topics directly relating to the work in progress such as confined 

space, shoring, and rigging. Excavator operator training was provided by experienced operators 

and was mostly on-the-job training (OJT). There was no written evidence that safety training 

included struck-by incidents, falling objects, or safety issues related to quick disconnects.

WORKER INFORMATION

The victim was a 21-year-old Hispanic male who was employed as a construction heavy 

equipment operator. He had been with the company for three years and had been training with 

this company on how to operate excavators for the past 12 months. It is not known whether he 

had prior experience operating similar equipment.

INCIDENT SCENE 

The incident scene was an outdoor construction site of a new housing project. The victim was 

digging a trench for storm drains. He had been working at this construction site for eight weeks 

when the incident occurred. 

THE EXCAVATOR AND ATTACHMENTS

The machine involved in this incident was a Hitachi hydraulic excavator (Exhibit 1). Attached to 

Exhibit 1. The excavator involved in the incident.
3 

the end of the boom was a hydraulic device called a quick coupler. Quick couplers are made by 

various manufacturers and have several designs. They are installed at the outer end of booms

by the pins that would normally be the mountings for the bucket or attachment (Exhibit 2). 

They facilitate the rapid exchange of working tools or buckets. The quick coupler involved in 

this incident was fully automatic. The distributor of the quick coupler was Steel Unlimited Inc. 

The coupler was hydraulically connected to a Geith hydraulic control panel in the excavator

operator’s cab (Exhibit 3). The control panel is designed to hydraulically lock the bucket to the 

quick coupler, and has an alarm to warn the operator when the mechanism malfunctions. The 

excavator operator typically confirms proper attachment of the bucket by raising the boom and 

testing the operation of the bucket prior to use.

Exhibit 2. A quick coupler similar to the one involved in this incident.

Exhibit 3. The automatic hydraulic quick coupler control panel.

INVESTIGATION

On the day of the incident, the victim arrived at the jobsite and began operating the excavator

to dig trenches for a concrete pipe drain system. When the supervisor arrived at the work 

location, he observed the victim maneuver the excavator as he pulled out two buckets of dirt 

from the trench and dumped it to the side. After removing a few loads of dirt from the trench, 

the victim swung the excavator boom away from the trench, stopped the boom in an elevated 

position and exited the cab. 

It is not known why the victim stopped the excavator boom and exited the cab. It is possible 

that the quick coupler locking mechanism did not fully engage and the victim was alerted by an 
4 

alarm on the control panel. The victim may have exited the cab to check on the bucket. The 

supervisor witnessed the victim approach the elevated bucket from underneath, and then the 

bucket detached, striking the victim (Exhibit 4). The decedent fell onto a small dirt berm at the 

edge of the trench. 911 was immediately called and the supervisor performed cardiopulmonary 

resuscitation (CPR) until emergency services arrived. The fire department provided advanced 

cardiac life support (ACLS) measures and transported the victim to the hospital where he was 

pronounced dead by the attending physician.

Exhibit 4. The bucket that disconnected from the coupling.

 

CAUSE OF DEATH

The cause of death, according to the death certificate, was blunt trauma. 

RECOMMENDATIONS

The CA/FACE investigator determined that, in order to prevent future incidents, employers 

should ensure that operators of excavators with quick coupling devices: 

Recommendation #1: Always lower the bucket to the ground before exiting the cab. 

Discussion: In this incident, the victim left the cab while the boom and bucket were still 

elevated. If operators become aware that the bucket is not operating properly, they should 

always lower the bucket to the ground before inspecting. If the bucket had been lowered to the 

ground, it would not have disconnected and fallen on the victim. 

Recommendation #2: Never walk/traverse beneath an excavator boom swing radius or 

elevated load.

Discussion: In this incident, the victim exited the cab and walked underneath the elevated bucket. 

All heavy equipment poses serious—even potentially fatal—risks to operators and others working 

in the vicinity. The relatively quick and far-reaching motion of the boom and bucket on an 

excavator is a particular source of danger. Manufacturers of excavators advise that no one should 
5 

walk below an elevated load or work within the boom swing radius during operation. If the victim 

had not walked under the elevated load, he would not have been struck by the bucket.

Recommendation #3: Train hydraulic excavator operators in the proper procedures for 

engaging excavation attachments and incorporate these procedures into the company’s safety 

and health program. 

Discussion: In this incident, the victim had received OJT training on how to operate the excavator. 

There was no documentation that he received specific instruction on the operation of quick 

couplers. If the victim had received increased training on excavator operations, he may have had 

greater knowledge about how quick couplers function and the the proper safety procedures to 

follow. With additional training, the victim may have lowered the boom to the ground, thereby 

preventing this incident.

REFERENCES

California Division of Occupational Safety and Health - Title 8 regulations - Subchapter 7. General

Industry Safety, Group 2. Safe Practices and Personal Protection. Article 7. Miscellaneous Safe 

Practices

California Division of Occupational Safety and Health - Title 8 regulations - Subchapter 4. 

Construction Safety Orders. Article 6. Excavations -§1541. General Requirements.

Preventing Injuries When Working with Hydraulic Excavators and Backhoe Loaders (NIOSH 

Publication No. 2004-107) https://www.cdc.gov/niosh/docs/wp-solutions/2004-107/pdfs/2004-

107.pdf?id=10.26616/NIOSHPUB2004107 

Australian Institute of Health and Safety (AIHS) Newsletter: Safety warning over semi-automatic 

quick hitches on excavators

https://www.aihs.org.au/news-and-publications/news/safety-warning-over-semi-automaticquick-hitches-excavators 

Safework Australia: Quick-hitches for earthmoving machinery (August 2016). 

https://www.safeworkaustralia.gov.au/doc/information-sheet-quick-hitches-earthmovingmachinery 

Wisconsin FACE Report 03WI003: Laborer Dies After Being Struck by Detached Excavator Bucket

https://www.cdc.gov/niosh/face/stateface/wi/03wi003.html 

Plant Assessor Quick Hitch: https://assessorclone.wpengine.com/nsw-quick-hitch-position/
6 

_____________________________ ______________________________

Hank Cierpich Robert Harrison, MD, MPH

FACE Investigator FACE Project Officer

_____________________________ _______________________________

Laura Styles Glenn Shor

Research Scientist Cal/OSHA CFOI Program 

 

 

July 2, 2021 

 

 

*******************************************************************************

FATALITY ASSESSMENT AND CONTROL EVALUATION PROGRAM

The California Department of Public Health, in cooperation with the Public Health Institute 

and the National Institute for Occupational Safety and Health (NIOSH), conducts 

investigations of work-related fatalities. The goal of the CA/FACE program is to prevent fatal 

work injuries. CA/FACE aims to achieve this goal by studying the work environment, the 

worker, the task the worker was performing, the tools the worker was using, the energy 

exchange resulting in fatal injury, and the role of management in controlling how these 

factors interact. NIOSH-funded, state-based FACE programs include: California, Kentucky, 

Massachusetts, Michigan, New York, Oregon, and Washington.

*******************************************************************************

Additional information regarding the CA/FACE program is available from:

California FACE Program

California Department of Public Health

Occupational Health Branch

850 Marina Bay Parkway, Building P, Third Floor

Richmond, CA 94804

www.cdph.ca.gov/face