California Department of Public Health

Occupational Health Branch

FATALITY ASSESSMENT AND CONTROL EVALUATION PROGRAM 

(CA/FACE) 

A pipefitter, working in a trench, died when he was struck by an excavator bucket 

that detached from a quick coupler

Case Report: 20CA002

SUMMARY

A pipefitter, working in a trench, died after being struck by an excavator bucket that detached 

from a quick coupling device (quick coupler) that was attached to the end of the boom. The 

operator of the excavator was curling the bucket into the boom when the bucket came loose and

fell on the victim. There was no competent person onsite the day of the incident. The CA/FACE 

investigator determined that, in order to prevent similar incidents, construction companies who 

operate excavators should: 

• Maintain and inspect quick couplers to prevent malfunctions that may cause an 

unintended release of the excavator’s bucket. 

• Ensure that a competent person is onsite to identify hazards and determine all 

necessary safety precautions, including preventing workers from walking/traversing 

beneath an excavator boom swing radius or elevated load.

INTRODUCTION

On Thursday, June 18, 2020, at approximately 9:30 a.m., a 67-year-old male pipefitter suffered 

fatal injuries when he was struck by an excavator bucket that detached from a quick coupler. 

The CA/FACE investigator received notification of the incident on June 23, 2020, from the 

Cal/OSHA Weekly Fatality Report. On August 24, and September 21, 2020, contact was made 

with the employer of the victim who was also the operator of the excavator. On October 2, 

2020, the CA/FACE investigator traveled to the location where the excavator was stored, and 

inspected the machine and took photos. The county coroner, fire department, and sheriff’s 

department reports of the incident were also obtained and reviewed. 

EMPLOYER

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

underground sewer and water pipe installation. The employer had been in business for 21 years 

and had five permanent full-time employees, including the victim. Part-time seasonal 

employees were hired depending on the workload. 
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WRITTEN SAFETY PROGRAMS AND TRAINING

The employer did not have a written safety program. Safe operation of excavators and other 

heavy equipment was accomplished through on-the-job training (OJT) by supervisory personnel

in both English and Spanish. There was no documentation that safety training included struckby incidents, falling objects, or safety issues related to quick couplers. 

WORKER INFORMATION

The victim was a 67-year-old Hispanic male who was employed as a pipefitter. He had been 

employed by this company for 15 years at the time of the incident.

INVESTIGATION

The incident scene was an outdoor construction site for new homes. The employer was installing 

underground sewer pipes, and had been at this worksite for six weeks prior to the incident. The 

only two people onsite the day of the incident were the victim and the employer who was also 

the operator of the excavator. The excavator machine (330) and quick coupler involved in this 

incident were both manufactured by Caterpillar (Exhibit 1). Quick couplers are hydraulic devices 

that are installed at the end of booms by pins that would normally be the mountings for the 

bucket or attachment. They facilitate the rapid exchange of working tools or buckets.

Exhibit 1. The excavator involved in this incident.
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Exhibit 1. The excavator involved in this incident.

At the time of the incident, the excavator operator was digging an additional trench next to 

existing underground sewer pipes. The new trench was going to accommodate more pipes that 

would be tied into the current sewer system (Exhibits 2 & 3). The depth of the trench was 

approximately nine feet. The deepest four feet were straight-sloped and wide enough to 

accommodate the new polyvinyl chloride (PVC) sewer pipes (Exhibit 4). The victim was likely in 

the trench acting as a spotter to signal to the operator where to move the bucket so that it 

would not damage existing pipe already in the trench. 

Exhibit 2 and 3. Alternate views of the trench.

Exhibit 4. Slope and depth of the trench.
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After digging a portion of the trench, the operator began curling the bucket (Exhibit 5) when it 

suddenly detached from the quick coupler (Exhibit 6) and struck the victim. The operator called 

911 and used a chain attached to the excavator boom to remove the bucket from the victim. 

Emergency response personnel arrived on scene and removed the victim from the trench. 

Despite life saving measures, the victim was pronounced dead at the scene.

Exhibit 5. Bucket being curled into the end of a Exhibit 6. The quick coupler attached to the end 

boom. of the boom. 

 

CAUSE OF DEATH

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

RECOMMENDATIONS

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

companies who operate excavators should: 

Recommendation #1: Maintain and inspect quick couplers to prevent malfunctions that may 

cause an unintended release of the excavator’s bucket. 

Discussion: The bucket detached from the quick coupler during operation, suggesting that there 

was an equipment malfunction. Although it is unknown why the bucket detached, the operator 

stated that the quick coupler had recently been repaired. It is unknown if the operator performed 

an inspection of the quick coupler prior to use. Employers using hydraulic excavators with quick 

couplers can prevent release of attachments by: 

• Inspecting all quick couplers to determine if they are subject to unexpected release 

hazards. 
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• Using newer models of quick couplers that have been specifically designed to prevent the 

unintended release of attachments.

• Following the manufacturer’s recommendations for maintenance and inspection of quick 

couplers. 

• Training workers in the proper use of quick couplers, including making visual inspections, 

proper procedures for engaging attachments, and methods for testing connections.

• Requiring workers to use proper procedures for engaging excavator attachments and 

incorporating the procedures into the company’s safety and health program.

It is possible that proper maintenance and inspection may have identified a mechanical 

problem with the quick coupler, thereby preventing detachment of the bucket. 

Recommendation #2: Ensure that a competent person is onsite to identify hazards and 

determine all necessary safety precautions, including preventing workers from

walking/traversing beneath an excavator boom swing radius or elevated load. 

Discussion: The victim was in the trench and likely within the radius of the boom when the 

excavator was in operation. When the operator curled the bucket, it detached and fell on the 

victim. According to the owner of the company, the bucket had never detached before. When 

employees are required to work in trenches deeper than five feet, a competent person is required 

to be onsite to perform the necessary daily inspections of excavations, and the precautions that 

are necessary and required. A competent person is defined by OSHA as someone who, by way of 

training or experience, is capable of identifying existing and predictable hazards in the 

surroundings or working conditions which are unsanitary, hazardous, or dangerous to 

employees, and who has the authorization to take prompt corrective measures to eliminate 

them. Employers should designate a competent person to conduct a Job Hazard Analysis (JHA) 

to identify high risk jobs and to determine appropriate employee training on recognized 

hazards and safe work procedures. This training should include trenching safety, operations in 

safe zone/danger zone, and inspection of equipment. If there had been a competent person 

onsite, the victim would most likely have not been underneath the boom swing radius and 

elevated load and struck by the bucket when it detached, thereby preventing this fatal 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 4. §1504. Definitions. 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 
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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/

_____________________________ ______________________________

Hank Cierpich Robert Harrison, MD, MPH

FACE Investigator FACE Project Officer

 

_____________________________ _______________________________ 

Laura Styles Glenn Shor

FACE Research Scientist Cal/OSHA CFOI Program 

 

 

 August 4, 2021

 

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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.

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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