1 

Preventing Excavator Quick Coupler Attachment 

Struck-by Fatalities and Injuries 

Excavator quick coupling devices (quick couplers) are widely used on construction job 

sites to rapidly change buckets and other attachments for various tasks. Quick

couplers can use powered, manual, or combination systems. Additionally, different

manufacturers use different mechanisms to keep the quick coupler engaged with the

bucket or other attachment. While this factsheet focuses on buckets, these

recommendations apply to any quick coupler attachment. There are three main

reasons why buckets or other attachments unintentionally fall from excavators using

quick couplers: (a) improper attachment of the bucket or attachment; (b) quick

coupler mechanical or hydraulic failure; or (c) operator opening of the quick coupler

in an unsafe position. 

 

Excavator involved in Case Study #1. 

Photo: CA FACE Program

Three main reasons why buckets unexpectedly fall from excavators – example of quick coupler with powered mechanism. 

Photos/Credit: Geith International, Ltd. 

Being struck by falling buckets or other attachments has caused severe injury or death to nearby workers. An

Occupational Safety and Health Administration (OSHA) Safety and Health Information Bulletin published in 2005 is

available on this topic. These types of incidents continue to occur, including the three incidents summarized in this fact

sheet. Employers, supervisors, and equipment suppliers should share and apply these recommended practices at the

worksite to help prevent deaths, injuries, and close calls related to excavator quick couplers. 
2 

Planning and Equipment Maintenance

• Use quick couplers manufactured with design features and processes to prevent unintentional release of 

buckets or other attachments. For example, some quick couplers include: 

o LED lights, alarms, or other alerting systems that indicate whether the pairing was successful. This helps

operators to engage the locking mechanism correctly. 

o Mechanisms which keep the bucket or other attachment in a default locked position even with a loss of 

hydraulic or electric power.

o Control systems that only allows the bucket or other attachment to be released in a safe position. 

• When possible, choose models of quick couplers that include smart technologies such as human detection 

systems and/or cameras that can alert operators when workers are within the swing radius of the excavator 

arm. 

• When possible, consider installing manufacturer-approved retrofit safety kits on older quick coupler devices.

• Plan and design job tasks such that manufacturer’s recommendations for equipment use are followed.

o Many manufacturer’s instructions state that ground workers should not be within the swing 

radius/swing zone of the excavator arm.

• Conduct regular maintenance of quick couplers according to manufacturer’s guidelines. 

Job Hazard Analysis

Employers should develop and implement policies for a designated person(s) to conduct a job hazard analysis (JHA) on

all worksites. The JHA will identify worksite hazards and necessary steps to eliminate or reduce those hazards. JHAs

should be regularly reviewed and discussed with workers during on-site safety meetings and/or with the use of toolbox

talks. 

Training

Train all workers on best work practices in languages they understand. Training should apply to the specific

equipment in operation and be based on the manufacturer’s recommendations. Effective training is an important

part of a strong health and safety program that follows the hierarchy of controls and can help create a strong

safety climate and safety culture. Workers should adhere, with supervisor reinforcement, to training guidelines and safe 

practices to protect themselves and their co-workers. Supervisors and equipment operators need to be aware that 

different manufacturers use different quick-coupling features. Therefore, equipment-specific training is necessary for 

workers using quick couplers. 

• All workers and supervisors who work with or near excavators should be trained on the following topics:

o Workers not standing, working, walking, or otherwise passing below an elevated bucket, attachment, or 

load.

o Procedures that will allow workers to perform necessary tasks outside of the excavator boom swing 

radius/swing zone. 

o Appropriate signals or other methods of communication between equipment operators and workers in 

the area.
3 

• Equipment operators and ground workers using quick couplers should be trained on the following topics:

o Proper use of quick coupling devices. This includes the manufacturer’s recommendations for inspection,

installation, maintenance, and use of the specific brand and model.

 Keep the quick couplers clean and free of debris.

 During maintenance, do not approach the equipment unless the attachment is resting on the 

ground.

o Proper procedures for engaging and disengaging excavation attachments.

 Use of approved quick coupler safety checks, visual indicators, and/or warning devices.

o Proper procedures for equipment operation in the presence of other workers. 

 Never operate equipment when ground workers are underneath a raised excavator arm and 

bucket or other attachment.

 Know where the excavator blind spots are located. 

o Know and understand load capacities for the specific equipment.

Safe Work Practices

Prior to Task or Activity

• Establish communication methods before starting work. Hand signals, radios or other agreed upon means of 

communication should be maintained between the operator and ground workers. 

• Ensure that machine operators always perform pre- and post-operation visual inspections on the excavator and 

quick coupler. This can identify any equipment deficiencies and prevent malfunctions that may cause an 

unintended release of the excavator’s bucket or work tool.

o Dirt and grease accumulation can create hazards for many quick coupler systems; proper maintenance 

includes keeping the quick couplers clean and free of debris.

o Ensure the operator performs a connection test and verification process, following all manufacturer 

instructions, prior to lifting or using an attachment. 

• Do not use any excavator that has signs of problems (such as damaged components, malfunctioning controls, 

faulty safety features, or other problems). For excavators removed from service for repair, lock the controls and 

attach warning tags (such as a “DO NOT OPERATE” sign) on the machine to prevent unauthorized operation.

• Ensure the bucket or other attachment is in a stable and level position before attaching or detaching the quick 

coupler.

During Task or Activity

• Do not allow workers to stand under, work, walk, or otherwise pass below an elevated bucket, attachment, or 

load.

• Follow manufacturer’s recommendations for use of equipment. 

o Follow procedures that will allow workers to perform necessary tasks outside of the excavator boom 

swing radius/swing zone. 

o When using a lift point on a quick coupler, note that many manufacturers will recommend lifting only 

after work tool attachments are removed from the quick coupler.

• Workers in the area of an excavator should keep the excavator in view and remain in view of the operator.

• Operators should lower the excavator arm/attachment to the ground before exiting the cab. 

• Equipment operators and members of the ground crew should have authority to stop work if they recognize 

unsafe conditions. 
4 

California FACE Reports

The NIOSH Fatality Assessment and Control Evaluation (FACE) program aims to prevent occupational fatalities by 

identifying and investigating work situations at high risk for injury. The program then formulates and disseminates

prevention strategies to those who can intervene in the workplace. California is one of the states funded by NIOSH to 

perform fatality assessments. Three recent reports from the California FACE program documented deaths from 

excavator buckets (weighing thousands of pounds) that fell from quick coupler attachments. 

California FACE Case Study #1

The bucket that disconnected from 

the coupler in Case Study #1. 

Photo: CA FACE program

In 2020, a 21-year-old heavy 

equipment trainee was killed 

when he attached a bucket using a 

quick coupler and stood below the 

bucket to inspect it. The bucket 

detached while the worker was 

beneath the bucket, and he was 

immediately struck and killed.

California FACE Case Study #2

View of trench and excavator boom 

in Case Study #2. Note – chain 

placed on equipment post-incident].

Photo: CA FACE program 

In 2020, a 67-year-old pipefitter 

was killed while working in a 

trench below the bucket of an 

excavator using a quick coupler. 

The bucket detached during 

digging operations and landed on 

the pipefitter. 

California FACE Case Study #3 

View into the trench where the victim was 

standing and where the bucket detached 

from the quick coupler in Case Study #3. 

[Note – chain placed on equipment postincident]. Photo: CA FACE program

In 2021, an excavator bucket 

detached from a quick coupler and

struck a 54-year-old worker. The 

crew was installing an 

underground storm drainage 

system on a residential street. The 

victim was in a trench when the 

excavator operator moved the 

boom over a trench to dig. The 

bucket detached from the quick 

coupler, fell, and struck and killed 

the victim. 

Get More Information

Find NIOSH products and get answers to workplace safety and health 

questions:

1-800-CDC-INFO (1-800-232-4636) | TTY: 1-888-232-6348

cdc.gov/cdc-info | cdc.gov/niosh

NIOSH monthly newsletter: cdc.gov/niosh/eNews

DHHS (NIOSH) Publication No. 2024-102

DOI: https://doi.org/10.26616/NIOSHPUB2024102

October 2023