U. S. Department of Labor
Occupational Safety and Health Administration
Directorate of Science, Technology and Medicine
Office of Science and Technology Assessment
Hazards of Inadequately Securing Hydraulic Excavator
Buckets When Using Quick Coupling Devices
Safety and Health Information Bulletin
SHIB 07-22-2005
Note: This Safety and Health Information Bulletin (SHIB) updates the "Revision of the
Unintended Release of Buckets from Quick Couplers on Hydraulic Excavators"
SHIB that was issued on August 26, 2004.
This Safety and Health Information Bulletin is not a standard or regulation, and
it creates no new legal obligations. The Bulletin is advisory in nature,
informational in content, and is intended to assist employers in providing a
safe and healthful workplace. Pursuant to the Occupational Safety and Health Act,
employers must comply with hazard-specific safety and health standards
promulgated by OSHA or by a state with an OSHA-approved state plan. In addition,
pursuant to Section 5(a)(1), the General Duty Clause of the Act, employers must
provide their employees with a workplace free from recognized hazards likely to
cause death or serious physical harm. Employers can be cited for violating the
General Duty Clause if there is a recognized hazard and they do not take
reasonable steps to prevent or abate the hazard. However, failure to implement
any recommendations in this Safety and Health Information Bulletin is not, in
itself, a violation of the General Duty Clause. Citations can only be based on
standards, regulations, and the General Duty Clause.
Preface
Following a fatal accident caused by the
unexpected release of an excavator bucket from a
quick coupling device on a hydraulic excavator, the
Occupational Safety and Health Administration
(OSHA) reviewed its Integrated Management
Information System (IMIS) accident data. The
accident data revealed 15 incidents since January
1998 involving the unanticipated release of excavator
buckets from quick couplers on hydraulic excavators.
Eight workers died in these incidents. OSHA urges
employers using quick couplers to inspect their quick
couplers and take appropriate measures to prevent
unintended bucket releases, which can result in death
or serious injuries.
Purpose
The purpose of this Safety and Health Information
Bulletin (SHIB) is to:
Alert employers and employees of the need
to follow manufacturer instructions regarding
the installation, use, testing, inspection, and
maintenance of quick coupling devices;
Explain how buckets and other attachments
can be unintentionally released from quick
couplers; and
Detail actions to prevent such unintended
releases.
Background
The OSHA Madison, Wisconsin Area Office
investigated a fatal accident where an excavator
bucket was released unexpectedly from a quick
coupler. OSHA’s statistical database revealed
fourteen additional incidents within the last six years
involving the use of this type of equipment where
excavator buckets unexpectedly released from quick
couplers. Of the fifteen accidents reported by Federal
and state OSHA offices, eight resulted in employee
fatalities.
Accident Description
The accident prompting this Safety and Health
Information Bulletin occurred at a site where a
contractor was installing water mains and laterals. An
excavation for a lateral had just been dug and an
employee entered that lateral to prepare to install the
pipe. The excavator operator changed buckets using
a quick coupler on the hydraulic excavator. When the
excavator was swung to continue digging on the main
line, the bucket became detached from the quick
coupler and rolled/slid into the lateral excavation,
striking the employee and killing him. The
investigation revealed that a locking pin had not been
manually installed on this coupler to prevent accidental
release of this attachment.
Quick Couplers
Most quick couplers are after-market devices that
have been used on hydraulic excavators for several
years and have steadily increased in popularity. They
enable contractors to quickly make attachment
changes on hydraulic excavators. Most quick
couplers have a lifting eye to use for lifting material.
(Figure 1).
Figure 1
By removing the bucket (Figure 2), the lifting capacity
of the excavator is increased by the weight of the
bucket. Additionally, removal of the bucket improves
the excavator operator’s line of vision during lifting.
Figure 2
Many contractors like to use a large bucket to do the
bulk of the digging and to then change to a smaller
bucket for fine tuning and working in tight areas. The
quick couplers also allow the operator to change from
a bucket attachment to various other attachments. In
most cases, the unexpected releases of buckets and
other attachments are likely caused by the failure to
properly engage and lock the quick couplers.
(Figures 3 & 4).
Figure 3
Figure 4
Other Information
Quick couplers are made by various manufacturers.
Manufacturers of quick couplers have recognized the
hazard of the bucket or other attachments being
unexpectedly released from the quick couplers and, in
many cases, have provided users with a retrofit
locking pin (Figures 5 & 6) which is manually inserted
behind the front lever (stick pin) or rear lever (link pin)
of the couplers to prevent unintended releases.
Figure 5
Figure 6
The National Institute for Occupational Safety and
Health also has studied the hazards associated with
hydraulic excavators and has issued DHHS
Publication No. 2004-107 entitled, "Preventing Injuries When Working with Hydraulic Excavators and Backhoe Loaders". This
publication addresses the hazard of excavator buckets
being unintentionally detached from a quick disconnect
mechanism.
Conclusions
Based upon experience, many manufacturers have
retrofitted existing quick couplers, designed new and
improved quick coupler systems, and developed safe
use and operating procedures. Overall, these
corrective actions have significantly decreased the
probability of a bucket or other attachment being
unintentionally released from a quick coupler.
However, unintended releases of buckets and other
attachments from quick couplers continue as
evidenced by the fatal accident in Madison, Wisconsin
and the IMIS accident data. Unintended releases
appear to continue because: not all employers/
contractors who use quick couplers are aware of the
hazard and of the manufacturers’ corrective actions;
some users fail to retrofit the quick coupler with
locking pins; and/or some users have insufficient
training on installation and testing procedures
associated with the use of such couplers. Given the
number of manufacturers and the diversity of quick
coupling devices, employers using quick couplers
should contact the manufacturer if they have questions
regarding the reliability of the quick coupling devices,
or to determine whether additional steps or
modifications are recommended in order for
employees to safely use a particular quick coupling
device.
Safety Measures to Prevent Accidents
Employers using hydraulic excavators with quick
coupling devices can protect employees from the
unintended release of attachments by:
Inspecting all quick couplers to determine if
they are subject to unexpected release
hazards. Determine whether a manually
installed locking pin and installation
procedures (or other retrofitting methods)
have been provided by the manufacturer.
If appropriate, obtaining and installing retrofits
recommended by the manufacturer, including
positive locking pins and other devices that
need to be manually installed.
Using an independent secondary system to
retain the bucket/work tool from falling, in the
event of a failure of the primary system. The secondary system can be
manual or automatic with a verification procedure for the user to check for
proper attachment.
Considering the use of 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 the quick coupler to prevent a malfunction of the quick coupler
that could cause an unintended release of the attachments.
Following the manufacturer’s installation procedures and recommendations
for using and testing quick coupler devices and 4 attachment connections
whenever an attachment is made.
Training employees in: the proper use of quick couplers; making visual
inspections; procedures for engaging attachments; and methods for testing
connections.
Requiring employees to use the proper procedures for engaging excavation
attachments and incorporating the procedures into the company’s safety and
health program.