Participate in all training programs offered
by your employers.
Only the worker who installs a lock and
tag should remove them after work is
complete and inspected.
Preventing
Worker Deaths from
Uncontrolled Release of Electrical,
Mechanical, and Other Types of Hazardous Energy
WARNING!
Workers
who install or service equipment and systems may be injured
or killed by the uncontrolled release of hazardous energy. |
The
National Institute for Occupational Safety and Health (NIOSH) requests
assistance in preventing the death or injury of workers exposed
to the unexpected or uncontrolled release of hazardous energy. In
this Alert, hazardous energy is any type of energy in sufficient
quantity to cause injury to a worker. Common sources of hazardous
energy include electricity, mechanical motion, pressurized air,
and hot and cold temperatures. Hazardous energy releases may occur
during the installation, maintenance, service, or repair of machines,
equipment, processes, or systems. Investigations conducted as part
of the NIOSH Fatality Assessment and Control Evaluation (FACE) Program
suggest that developing and following hazardous energy control procedures
could prevent worker injuries and fatalities.
This
Alert describes five fatal incidents in which workers contacted
uncontrolled hazardous energy during installation, maintenance,
service, or repair work. To prevent such deaths, the recommendations
in this Alert should be followed by every employer, manager, supervisor,
and worker who installs, maintains, services, or repairs machines,
equipment, processes, or systems. NIOSH requests that trade journal
editors, safety and health officials, and others responsible for
worker safety and health bring this Alert to the attention of employers
and workers who are at risk.
Only the worker who installs a lock and
tag should remove them after work is
complete and inspected.
Number
of Workers Killed
No
detailed national data are available on the number of workers killed
each year by contact with uncontrolled hazardous energy. However,
during the period 1982-1997, NIOSH investigated 1,281 fatal incidents
as part of their FACE Program. Of these, 152 involved installation,
maintenance, service, or repair tasks on or near machines, equipment,
processes, or systems. Because the FACE program was active in only
20 States between 1982 and 1997, these fatalities represent only
a portion of the U.S. workers who were killed by contact with uncontrolled
hazardous energy.
Contributing
Factors
Review
of these 152 incidents suggests that three related factors contributed
to these fatalities:
- Failure to
completely de-energize, isolate, block, and/or dissipate the
energy source (82% of the incidents, or 124 of 152)
-
Failure
to lockout and tagout energy control devices and isolation points
after de-energization (11% of the incidents, or 17 of 152)
-
Failure
to verify that the energy source was de-energized before beginning
work (7% of the incidents, or 11 of 152)
In
a study conducted by the United Auto Workers (UAW), 20% of the fatalities
(83of 414) that occurred among their members between 1973 and 1995
were attributed to inadequate hazardous energy control procedures
specifically, lockout/tagout procedures. The energy sources involved
in these fatalities included kinetic, potential, electrical, and
thermal energy [UAW 1997].
Current
Occupational Safety and Health Administration (OSHA) standards for
general industry are established to prevent injuries and fatalities
from contact with hazardous energy [29 CFR* 1910.147]. This standard
requires employers to "establish a program consisting of energy
control procedures, employee training and periodic inspections to
ensure that before any employee performs any servicing or maintenance
on a machine or equipment where the unexpected energizing, start
up or release of stored energy could occur and cause injury, the
machine or equipment shall be isolated from the energy source, and
rendered inoperative."
*Code
of Federal Regulations. See CFR in references.
Other
OSHA standards for general industry cite the need for de-energizing
electrical energy and locking and tagging electrical circuits and
equipment before performing maintenance and servicing tasks. The
following OSHA standards contain lockout/tagout-related requirements:
1910.146 Permit-Required
Confined Spaces
1910.177 Servicing Multi-Piece and
Single Piece Rim Wheels
1910.178 Powered Industrial Trucks
1910.179 Overhead and Gantry Cranes
1910.181 Derricks
1910.213 Woodworking Machinery
1910.217 Mechanical Power Presses
1910.218 Forging Machines
1910.261 Pulp, Paper, and Paperboard
Mills
1910.262 Textiles
1910.263 Bakery Equipment
1910.265 Sawmills
1910.269 Electric Power Generation,
Transmission, and Distribution
1910.272 Grain Handling
1910.305 Wiring Methods, Components,
and Equipment for General Use
1910.306 Specific Purpose Equipment
and Installations
1910.333 Selection and Use of Work
Practices
OSHA
standards for construction also contain requirements for protecting
workers from electrical hazards [29 CFR 1926.416 and 29 CFR 1926.417].
These standards require that workers exposed to any part of an electrical
power circuit be protected through de-energizing and grounding of
the circuit or through appropriate guarding. These standards also
require that all de-energized circuits be rendered inoperable and
tagged out.
FORMS OF HAZARDOUS
ENERGY |
Workers
may be exposed to hazardous energy in several forms and combinations
during installation, maintenance, service, or repair work. A comprehensive
hazardous energy control program should address all forms of hazardous
energy [NIOSH 1983]:
- Kinetic
(mechanical) energy in the moving parts of mechanical systems
-
Potential
energy stored in pressure vessels, gas tanks, hydraulic
or pneumatic systems, and springs (potential energy can be released
as hazardous kinetic energy)
-
Electrical
energy from generated electrical power, static sources,
or electrical storage devices (such as batteries or capacitors)
-
Thermal
energy (high or low temperature) resulting from mechanical
work, radiation, chemical reaction, or electrical resistance
As
part of the FACE Program from 1982 through 1997, NIOSH investigated
152 fatal incidents in which workers contacted uncontrolled hazardous
energy. The following case reports summarize five of these investigations.
Case
No. 1-Uncontrolled Kinetic Energy
A
25-year-old male worker at a concrete pipe manufacturing facility
died from injuries he received while cleaning a ribbon-type concrete
mixer. The victim's daily tasks included cleaning out the concrete
mixer at the end of the shift. The clean-out procedure was to shut
off the power at the breaker panel (approximately 35 feet from the
mixer), push the toggle switch by the mixer to make sure that the
power was off, and then enter the mixer to clean it.
No
one witnessed the event, but investigators concluded that the mixer
operator had shut off the main breaker and then made a telephone
call instead of following the normal procedure for checking the
mixer before anyone entered it. The victim did not know that the
operator had de-energized the mixer at the breaker. Thinking he
was turning the mixer off, he activated the breaker switch and energized
the mixer. The victim then entered the mixer and began cleaning
without first pushing the toggle switch to make sure that the equipment
was de-energized. The mixer operator returned from making his telephone
call and pushed the toggle switch to check that the mixer was de-energized.
The mixer started, and the operator heard the victim scream. He
went immediately to the main breaker panel and shut off the mixer.
Within
30 minutes, the emergency medical service (EMS) transported the
victim to a local hospital and then to a local trauma center. He
died approximately 4 hours later [NIOSH 1995].
Case
No. 2-Uncontrolled Electrical Energy
A
53-year-old journeyman wireman was electrocuted when he contacted
two energized, 6.9 -kilovolt buss terminals. The victim and two
coworkers (all contract employees) were installing electrical components
of a sulfur dioxide emission control system in a 14-compartment
switch house.
The
circuit breaker protecting the internal buss within
the switch house had been tripped out and marked with a tagbut
it had not been secured by locking. This procedure was consistent
with the hazardous energy control procedures of the power plant.
A
conducting bar, rod, or tube that carries heavy currents to supply
several electric circuits.
The
victim and his coworkers were wiping down the individual compartments
before a prestartup inspection by power plant personnel. Without
the knowledge of the victim and his coworkers, power plant personnel
had energized the internal buss in the switch house. When the victim
began to wipe down one of the compartments at the south end of the
switch house, he contacted the A-phase buss terminal with his right
hand and the C-phase buss terminal with his left hand. This act
completed a path between phases, and the victim was electrocuted.
A
coworker walking past the victim during the incident was blown backward
by the arcing and received first-degree flash burns on his face
and neck. A second coworker at the north end of the switch house
heard the explosion and came to help. He notified the contractor's
safety coordinator by radio and requested EMS. The EMS responded
in about 15 minutes and transported the victim to a local hospital
emergency room where he was pronounced dead [NIOSH 1994].
Case
No. 3-Uncontrolled Kinetic Energy
A
38-year-old worker at a county sanitary landfill died after falling
into a large trash compactor used to bale cardboard for recycling.
The cardboard was lifted 20feet by a belt conveyor and fed through
a 20- by 44-inch opening into a hopper. The hopper had automatic
controls that activated the baler when enough material collected
in the baling chamber. When the baler was activated, material in
the chamber was compressed by a ram that entered the chamber from
the side. Excess material above the chamber was trimmed by a shearer.
On
the day of the incident, cardboard jammed at the conveyor discharge
opening. Without stopping, de-energizing, or locking out the equipment,
the victim rode the conveyor up to the discharge opening to clear
the jam. He fell into the hopper and the baling cycle was automatically
activated, amputating his legs. The victim bled to death before
he could be removed from the machine [Colorado Department of Public
Health and Environment 1994].
Case
No. 4-Uncontrolled Potential Energy
The
32-year-old owner of a heavy equipment maintenance business died
after a wheel and tire assembly exploded during repair work. The
victim was removing the assembly from a test roller when it exploded
and struck him with the flying split rim of the wheel.
The
test roller was a large, two-wheeled cart that carried about 60,000
pounds of concrete weights. The roller was used in highway construction
to test road surfaces for proper compaction.
The
victim had been working as a subcontractor to repair the wheel and
tire assembly, which had been smoking earlier in the day and was
believed to be rubbing against the concrete weights. The assembly
consisted of a two-piece outside rim and an inside ring retainer
that was held together and mounted on the axle by 20 wheel bolts
and nuts. Normal air pressure for the mounted tire was 70 psi.
The
victim raised and blocked the roller. Without discharging the air
from the tire and using no personal protective equipment, he began
to remove the wheel nuts using a pneumatic impact wrench. He had
no training or experience with this type of work or in the servicing
of this type of wheel. He did not realize that only some of the
bolts held the wheel tire assembly to the axle. The remainder held
the outer half of the rim to the inside half, securing the tire
to the wheel. As the victim removed the nineteenth wheel nut, the
pressurized air in the tire discharged explosively, causing the
split rim to fly off the wheel and strike him. He died from cerebral
contusions and lacerations [Minnesota Department of Health 1992].
Case
No. 5-Uncontrolled Kinetic and Thermal Energy
A
33-year-old janitorial worker died after he was trapped inside a
linen dryer at a hospital laundry while cleaning plastic debris
from the inside of the dryer drum. The cleaning task (which usually
took 15 minutes to an hour) involved propping open the door to the
dryer with a piece of wood and entering the 4- by 8-foot dryer drum.
The melted debris was removed by scraping and chiseling it with
screwdrivers and chisels. The dryer was part of an automated system
that delivered wet laundry from the washer through an overhead conveyor
to the dryer, where it was dried during a 6-minute cycle with air
temperatures of 217° to 230°F. The
system control panel was equipped with an error light that was activated
if the dryer door was open, indicating that the dryer was out of
service.
On
the night of the incident, the victim propped the door open and
entered the dryer drum without de-energizing or locking out the
dryer. He began to clean the inside of the drum. Although the error
light had been activated when the door was propped open, the signal
was misinterpreted by a coworker, who restarted the system. When
the system was restarted, the overhead conveyor delivered a 200-pound
load of wet laundry to the dryerknocking out the wooden door
prop, trapping the victim inside, and automatically starting the
drying cycle. The victim remained trapped inside until the cycle
was completed and was discovered when the load was discharged from
the dryer. He died thirty minutes later of severe burns and blunt
head trauma [Massachusetts Department of Public Health 1992].
Review
of the NIOSH FACE data indicates that three related factors contribute
to injuries and deaths that occur when workers perform installation,
maintenance, service, or repair work near hazardous energy sources:
- Failure to
completely de-energize, isolate, block, and/or dissipate the
hazardous energy source
-
Failure
to lockout and tagout energy control devices and isolation
points after the hazardous energy source has been de-energized
-
Failure
to verify that the hazardous energy source was de-energized
before beginning work
These
fatalities could have been prevented if comprehensive hazardous
energy control procedures had been implemented and followed.
NIOSH
recommends that employers implement the following steps to prevent
injuries and deaths of workers who must work with hazardous energy
in their jobs:
Comply with OSHA regulations.
Develop
and implement a hazardous energy control program.
Identify
and label all hazardous energy sources.
De-energize,
isolate, block, and/or dissipate all forms of hazardous energy
before work begins.
Establish
lockout/tagout programs that
require
workers to secure energy control devices with their own individually
assigned locks and keysonly one key for each lock
the worker controls;
require
that each lock used to secure an energy control device be
clearly labeled with durable tags to identify the worker assigned
to the lock;
make
sure that the worker who installs a lock is the one who removes
it after all work has been completed; and
if
work is not completed when the shift changes, workers arriving
on shift should apply their locks before departing workers
remove their locks.
Verify
by test and/or observation that all energy sources are de-energized
before work begins.
Inspect
repair work before reactivating the equipment.
Make
sure that all workers are clear of danger points before re-energizing
the system.
Train
ALL workers in the basic concepts of hazardous energy control.
Include
a hazardous energy control program with any confined-space entry
program.
Encourage
manufacturers to design machines and systems that make it easy
to control hazardous energy.
Use of master keys should be reserved for unusual
circumstances when the worker is absent from the workplace. However,
if master keys are necessary, keep them under supervisory control.
List the proper procedures for using them in the written program
for controlling hazardous energy.
These
recommendations are described in more detail in the following sections.
1.
Comply with OSHA regulations.
Employers
and workers must comply with OSHA regulations for controlling hazardous
energy during maintenance and installation work (see 29 CFR 1910.146,
1910.147, 1910.177, 1910.178, 1910.179, 1910.181, 1910.213, 1910.217,
1910.218, 1910.261, 1910.262, 1910.263, 1910.265, 1910.269, 1910.272,
1910.305, 1910.306, 1910.333, 1926.416, and 1926.417). OSHA standards
and accepted safe work practices require employers to ensure that
all hazardous energy sources are de-energized before work begins.
If these sources cannot be de-energized, OSHA requires employers
to protect workers with insulation, guarding, and appropriate personal
protective equipment.
2.
Implement a hazardous energy control program.
Employers
should develop and implement a written hazardous energy control
program that, at a minimum,
describes
safe work procedures,
establishes
formal lockout/tagout procedures,
trains
all employees in the program, and
enforces
the use of the procedures (including disciplinary action for failure
to follow them).
Hazardous
energy control programs should outline the following safe work practices:
- Identify
tasks that may expose workers to hazardous energy.
-
Identify
and de-energize all hazardous energy sources, including
those in adjacent equipment.
-
Lockout
and tagout all energy-isolating devices to prevent inadvertent
or unauthorized reactivation or startup.
-
Isolate,
block, and/or dissipate all hazardous sources of stored
or residual energy, including those in adjacent equipment.
-
Before
beginning to work, verify energy isolation and de-energization,
including that in adjacent equipment or energy sources.
-
After
work is complete, verify that all personnel are clear of danger
points before re-energizing the system.
Hazardous
energy control among work groups must be coordinated when multiple
employers are involved in large projects and when shift changes
occur during such activities. Outside contractors should work with
the facility owner to make sure that an adequate hazardous energy
control program is implemented specifically for contract workers.
3.
Identify and label all hazardous energy sources.
Employers
should use jobsite surveys to ensure that all hazardous energy
sources (including those in adjacent equipment) are identified before
beginning any installation, maintenance, service, or repair
tasks. Hazardous energy includes mechanical motion, potential or
stored energy, electrical energy, thermal energy, and chemical reactions.
Energy-isolating devices such as breaker panels and control valves
should be clearly labeled [NIOSH 1983].
4.
De-energize, isolate, block, and/or dissipate all forms of hazardous
energy.
All
forms of hazardous energy should be de-energized, isolated, blocked,
and/or dissipated before workers begin any installation,
maintenance, service, or repair work. The method of energy control
depends on the form of energy involved and the available means to
control it. Energy is considered to be isolated or blocked
when its flow or use cannot occur [NIOSH 1983].
To
isolate or block energy, take the following steps:
- Disconnect
or shut down engines or motors that power mechanical systems.
-
De-energize
electrical circuits by disconnecting the power source from the
circuit.
-
Block
fluid (gas, liquid, or vapor) flow in hydraulic, pneumatic,
or steam systems by using control valves or by capping or blanking§
the lines.
-
Block
machine parts against motion that might result from gravity
(falling).
§Lines
can be blanked by inserting a solid plate between the flanges of
a joint.
Some
forms of energy must also be dissipated after a system has been
de-energized. System components such as electrical capacitors, hydraulic
accumulators, or air reservoirs may retain sufficient energy to
cause serious injury or death even though the component has been
de-energized, isolated, or blocked from the system and locked out.
Energy
can be dissipated by taking the following steps:
- Vent fluids
from pressure vessels, tanks, or accumulators until internal
pressure is at atmospheric levels. However, do not vent vessels
or tanks containing toxic, flammable, or explosive substances
directly to the atmosphere.
-
Discharge
capacitors by grounding.
-
Release
or block springs that are under tension or compression.
-
Dissipate
inertial forces by allowing the system to come to a complete
stop after the machine or equipment has been shut down and isolated
from its energy sources.
5.
Establish lockout/tagout programs requiring individually assigned
locks and keys to secure energy control devices.
Lockout/tagout
programs should be based on the principle of only one key for
each lock the worker controls.** This means the following:
Workers
are assigned individual locks operable by only one key for use
in securing energy control devices (breaker panels, control valves,
manual override switches, etc.).
Each
worker maintains custody of the key for each of his or her assigned
locks.**
Each
lock is labeled with a durable tag or other means that identifies
its owner.
When
work is performed by more than one worker, each worker applies
his or her own lock to the energy-securing device. Scissors- type
hasps made of hardened steel are available to facilitate the use
of more than one lock to secure an energy control device.
All
de-energized circuits and systems are clearly labeled with durable
tags.
The
worker who installs a lock is the one who removes it after all
work has been completed [NIOSH 1988].
If
work is not complete when the shift changes, workers arriving
on shift apply their locks before departing workers remove their
locks.
Because
tags can be easily removed, they are not a substitute for locks.
Workers are safest with a program that uses both locks and
warning tags to prevent systems from being inadvertently re-energized
[NIOSH 1988].
**Use
of master keys should be reserved for unusual circumstances when
the worker is absent from the workplace. However, if master keys
are necessary, keep them under supervisory control. List the proper
procedures for using them in the written program for controlling
hazardous energy.
6.
Verify that all energy sources are de-energized before work begins.
Employers
should establish and enforce company policies requiring workers
to verify that all energy sources are de-energized before work begins.
This verification should ensure that all energy sources (including
stored energy) are controlled (that is, de-energized, isolated,
blocked, and/or dissipated) before work begins. Appropriate testing
equipment should be required as needed.
7.
Inspect repair work before reenergizing the equipment.
To
ensure that equipment will operate as expected when it is re-energized,
employers should require qualified persons to inspect completed
installation, maintenance, service, or repair work. The inspection
should verify that installation, repairs, and modifications were
performed correctly and that the correct replacement parts were
used. When equivalent or updated parts must be substituted for original
parts, the system may need to be modified. Re-energized equipment
should be closely monitored for several operating cycles to ensure
that it is functioning correctly and safely.
8.
Make sure that all persons are clear of danger points before re-energizing
the system.
Employers
should develop procedures to verify that all persons are clear of
danger points before re-energizing the system. Locks and tags should
be removed only by the workers who installed themand only
after workers have been cleared from the danger points. This may
require visual inspections and searches of areas around machinery
or electrical circuits to assure that workers will not be exposed
to the release of hazardous energy when equipment is re-energized.
Workers should be informed about impending equipment start-up with
warning devices they can see and hear. Such devices will help assure
that workers are clear before equipment is re-energized.
9.
Train workers in the basic concepts of hazardous energy control.
Employers should train ALL workers in the basic concepts of hazardous
energy control, including energy isolation, locking and tagging
of control devices, verifying de-energization, and clearing danger
points before re-energizing equipment. Workers whose duties involve
installation, maintenance, service, or repair work should be trained
in the detailed control procedures required for their particular
equipment. This training should enable workers to identify tasks
that might expose them to hazardous energy and the effective methods
for its control.
10. Include a hazardous energy
control program with any confined-space entry program.
When
work requires entry into confined spaces such as utility vaults
or tanks, employers should incorporate a hazardous energy control
program as part of their confined-space entry programaccording
to OSHA standards [29 CFR 1910.146 and 1910.147] and published NIOSH
guidelines [NIOSH 1979, 1987].
11.
Design machines and systems that make it easy to control hazardous
energy.
Employers
should encourage manufacturers to design control valves, switches,
and equipment that are easy to access and lockout.
Principal
contributors to this Alert were Paul Moore and Tim Pizatella of
the NIOSH Division of Safety Research (DSR). Injury data were provided
by the Health and Safety Department, International Union, United
Auto Workers (UAW). Cases presented in this Alert were contributed
by Georjean Madery, formerly of the Minnesota Department of Health;
Lyle McKenzie, Colorado Department of Health; and Jon Lifvergren,
formerly of the Massachusetts Department of Health. Stephanie Pratt,
DSR, provided data analysis, and Larry Reed, Division of Physical
Sciences and Engineering, provided many helpful comments and suggestions.
Dwayne Smith, formerly of DSR, provided the first working draft
of this Alert.
Please
direct comments, questions, or requests for additional information
to the following:
Dr.
Nancy A. Stout, Director
Division of Safety Research
National Institute for Occupational Safety
and Health
1095 Willowdale Road
Morgantown, West Virginia 26505-2888
Telephone:
304-285-5894; or call
1-800-35-NIOSH (1-800-356-4674).
We
greatly appreciate your help in protecting the safety and health
of U.S. workers.
Linda Rosenstock,
M.D., M.P.H.
Director, National Institute for
Occupational Safety and Health
Centers for Disease Control and
Prevention
CFR.
Code of Federal regulations. Washington, DC: U.S. Government Printing
Office, Office of the Federal Register.
Colorado
Department of Public Health and Environment [1994]. Thirty-eight-year-old
recycling technician dies as a result of injuries sustained when
he fell into a cardboard compactor. Denver, CO: Colorado Department
of Health and Environment, Colorado Fatality Assessment and Control
Evaluation (FACE) Report No. 94CO029.
Massachusetts
Department of Public Health [1992]. Custodian dies in a confined
space in a hospital laundry. Boston, MA: Massachusetts Department
of Public Health, Massachusetts Fatality Assessment and Control
Evaluation (MA FACE) Report No.91-02.
Minnesota
Department of Health [1992]. Owner of heavy equipment maintenance
business dies after being struck by an exploding split rim of a
test roller tire. Minneapolis, MN: Minnesota Department of Health,
Minnesota Fatality Assessment and Control Evaluation (MN FACE) Report
No.MN9208.
NIOSH
[1979]. Criteria for a recommended standard: working in confined
spaces. Morgantown, WV: U.S. Department of Health, Education, and
Welfare, Public Health Service, Center for Disease Control, National
Institute for Occupational Safety and Health, DHEW (NIOSH) Publication
No. 80-106.
NIOSH
[1983]. Guidelines for controlling hazardous energy during maintenance
and servicing. Morgantown, WV: U.S. Department of Health and Human
Services, Public Health Service, Centers for Disease Control, National
Institute for Occupational Safety and Health, DHHS (NIOSH) Publication
No. 83-125.
NIOSH
[1987]. A guide to safety in confined spaces. Morgantown, WV: U.S.
Department of Health and Human Services, Public Health Service,
Centers for Disease Control, National Institute for Occupational
Safety and Health, DHHS (NIOSH) Publication No. 87-113.
NIOSH
[1988]. NIOSH testimony on the Occupational Safety and Health Administrations
proposed rule on the control of hazardous energy sources (lockout/tagout),
September 8, 1988, OSHA Docket No.S012A. Cincinnati, OH: U.S. Department
of Health and Human Services, Public Health Service, Centers for
Disease Control, National Institute for Occupational Safety and
Health.
NIOSH
[1994]. Journeyman wireman electrocuted after contacting energized
switchgear components at power plant West Virginia. Morgantown,
WV: U.S. Department of Health and Human Services, Public Health
Service, Centers for Disease Control and Prevention, National Institute
for Occupational Safety and Health, Fatality Assessment and Control
Evaluation (FACE) Report No. 9410.
NIOSH
[1995]. Laborer fatally injured while cleaning concrete mixer Tennessee.
Morgantown, WV: U.S. Department of Health and Human Services, Public
Health Service, Centers for Disease Control and Prevention, National
Institute for Occupational Safety and Health, Fatality Assessment
and Control Evaluation (FACE) Report No. 9512.
UAW
[1997]. An analysis of trends in fatal injuries related to lock-out
failure in UAW-represented worker populations. Detroit MI: International
Union, United Automobile, Aerospace and Agricultural Implement Workers
of America UAW, UAW Health and Safety Department.
DISCLAIMER
Mention of any company or product does not constitute endorsement
by the National Institute for Occupational Safety and Health.
This document is in the public domain and may be freely
copied or reprinted.
|
Copies of this and other NIOSH documents are available from
National Institute for Occupational Safety and Health
4676 Columbia Parkway
Cincinnati, OH 45226-1998
Fax number: (513) 533-8573
Telephone number: 1-800-35-NIOSH
(1-800-356-4674)
E-mail: pubstaft@cdc.gov
To receive other information about occupational safety and
health
problems, call 1-800-35-NIOSH (1-800-356-4674), or visit the
NIOSH Home Page
on the World Wide Web at http://www.cdc.gov/niosh/homepage.html
DHHS (NIOSH)Publication
No. 99-110
August 1999
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