Subject: Pug Mill Operator Killed After Entanglement
On November 19, 1996, a 25yearold female pug mill operator at a brick manufacturing plant was killed after her clothing became caught in a rotating shaft. She was strangled as the rotating shaft tightened her clothing around her neck, restricting her airway. In order to prevent similar incidents from occurring, FACE investigators recommend:
On November 21, 1996, KY FACE was notified of an occupational
fatality on November 19 involving a 25yearold female
at a brick manufacturing facility. Contact with the employer was
made and an investigation initiated. At the employer's request,
the onsite investigation did not take place immediately.
On February 25, 1997, a site visit was made and photographs were
taken of the scene. Interviews were held with the coroner, EMS
director, fire and rescue personnel who responded to the scene,
a police officer knowledgeable of the case, the OSH compliance
officer and the company vicepresident. Copies of the coroner's
report and the death certificate were obtained.
This familyowned company has been in operation at this site since 1970. Daytoday operations are handled by the company founder and his three sons. The company had one previous fatality in the early 1970s when an employee fell from a roof into a clay grinding machine. No other serious injuries have occurred at the facility. The vicepresident reported a fairly consistent work crew, with approximately 50 percent earning more than minimum wage. On average, 20 new employees are hired each year. The decedent had been the only female who worked in the plant.
On the morning of the incident, the local fire and rescue squad
had done a company inspection of this facility. These inspections
are completed once each year at all manufacturing settings in
the community to familiarize the rescue squad with the settings,
potential hazards, means of access, sources of water, power lines,
and other site features or obstacles to performing a rescue.
The victim had been employed at this company for about three months
and had worked a variety of laborer jobs in the community prior
to beginning work at this plant. She was of average height and
weight. She had one child. The normal work shift at the plant
is from 7:00 am to 4:00 PM with an hour break for lunch.
The employer in this case was a familyowned brick manufacturer which began operation in 1970 and employed about 45 persons at the time of the incident. Approximately 13 million (2.0" x 7.5' x 3.0") bricks are produced each year. In addition, two million 1/2" x 7.5" x 3.0" bricks are produced primarily for export. The company produces approximately 20 different colors and textures of brick. The brick is used primarily for residential and commercial building in the region. As well, bricks manufactured by other companies are sold by the company.
Raw dry clay delivered to the site from a neighboring county is
ground to a powder and transported by conveyer to a pug mill where
water is added and the product mixed by a rotating auger and forced
through the machine. The moistened clay is sent through an extruder
that produces a 3.0" x 7.0" sized continuous rectangle
which is put onto a conveyer for cutting. Thin wires then cut
the rectangle into the appropriate size brick. The bricks, resting
on a continuous conveyer, are moved to the stacking area where
the moist firm bricks are stacked into 4' x 4 x 4' stacks on flatbed
steelwheel mobile cars for drying. To remove all the moisture,
the brickfilled cars are moved through a 400degree
gasfired oven. The cars are then moved through the natural
gas kiln where the bricks are fired for three days at nearly 2000
degrees. The entire process, from clay delivery to finished bricks,
takes five days. One building houses the operation, and about
20 employees are required to work on the line. Natural ventilation
in the building results in a cold environment in winter and hot
in the summer. Employees must endure cold temperatures while working
in winter even though the kiln is in the building.
The victim had been provided with onthejob training
during her first week of work at the company. Her job was to stand
on a 21/2' x 12' platform that was about four feet off the
ground and made of steel grating. The platform paralleled the
pug mill and was accessed by five stairs. Her job was to observe
and monitor the amount of moisture added to the clay and periodically
spray water with a handheld garden hose when the clay became
too thick and stuck to the sides of the pug mill. Power for the
pug mill is controlled by an operator on the ground level about
18 feet away. The control panel is equipped with an emergency
shutoff. The victim had mastered her job and was performing
satisfactorily. Part of her responsibility was to notify the worker
near the controls if the unit was malfunctioning.
The power for the pug mill rotation is transmitted by an approximately
12foot long, 31/2inch diameter steel shaft with
couplings that travels the length of the unit at the level of
the operator's feet. This shaft rotates at about 30 rpm and is
powered by a 250hp electric motor. At the time of the incident
the shaft was not guarded. The edge of the shaft is about five
inches from the walking surface of the platform. At one point
along the shaft a coupling measuring about seven inches in diameter
comes within three inches of the work platform. When the pug mill
is shut off, the shaft continues to rotate for about five seconds.
It was reported that once in the past an operator caught his pant
leg on the coupling and his pants were torn off.
On the day of the incident, the victim began her shift at the
usual time of 7:00 am, taking her position to monitor the pug
mill. Work progressed normally until shortly after 2:00 PM, when
a coworker heard her cries for assistance, saw that she
was caught in the machinery, and shut it off at the emergency
switch located 18 feet away at ground level. He then attempted
to free her and cut away some of her clothing. By this time another
coworker had called 911. It appears the victim's clothing
on her left arm wrapped around the shaft at the coupling, pulling
her arm and torso into the rotating shaft.
Emergency medical services (EMS) received the call at 2:16 PM.
One EMT and one paramedic were immediately dispatched and arrived
at the scene at 2:45. The fire and rescue squad were already at
the scene. CPR was not initiated. The victim was hooked up to
the monitor and was asystolic. The coroner was called at 2:43
PM and pronounced the victim dead at the scene. Her clothing,
a thick winter coat, was cut from her in order to free her from
the unit. She was then taken to the morgue. EMS left the scene
at 5:20 PM.
Although the incident was not witnessed, it is thought that the
victim dropped her cigarettes or lighter onto the platform and
in attempting to retrieve them caught the left sleeve of her heavy
overcoat on the exposed rotating drive shaft. Her left arm wound
around the shaft as it continued to rotate. Her arm and clothing
were wrapped so tightly that her ability to breathe was restricted.
CAUSE OF DEATH
The cause of death on the coroner's report was asphyxiation due
to clothing wrapped around neck due to clothing being caught in
machine. Toxicology report was negative.
Recommendation #1: Machines with rotating parts should have guards to prevent worker contact.
Discussion: In this case, the 12foot long rotating
shaft and coupling did not have a safety guard. Although it was
rotating at just 30 rpm, it still presented a hazard to the worker.
By the time of the investigation, the shaft had a complete guard
covering its length. Had this guard been in place at the time
of the incident, the tragedy could have been averted. As in the
OSH standards for general industry, all exposed parts of horizontal
shafting seven feet or less from floor or working platform should
be protected by a stationary casing enclosing shafting completely.
In this case, the victim came into contact with the exposed rotating
coupling. Had the coupling and shaft been covered, she would not
have made contact and become entangled. At the time of the site
visit, the shaft was covered with a welded steel cage.
Recommendation #2: Employers should designate a competent person 1 to conduct regular safety inspections and coordinate routine safety and injury prevention meetings. As well, employers should encourage workers to actively participate in workplace safety.
Discussion: The employer reported that there was a person on staff to do first aid and CPR, but did not indicate that there was a safety program or policy in place. Employers should designate a person to conduct regular safety rounds to identify potential hazards. In this case, recognition of the rotating shaft and its proximity to the work zone on the platform could have prompted an intervention such as covering the shaft to eliminate the potential for contact.
Employers should encourage all workers to actively participate
in workplace safety and ensure that all workers understand the
role they play in the prevention of occupational injury. In this
instance the victim was working on an elevated work surface which
was in close proximity to a hazard. Other workers had likely seen
this work setting and were familiar with the hazard. Employers
should instruct workers of their responsibility to participate
in making the workplace safer.
Recommendation #3: Design a kill switch within reach of the operator to disengage the power and allow free movement of the shaft.
Discussion: Rescue squad workers could not rotate the shaft
using a 4foot pipe wrench to release pressure and free the
victim. If the unit had a kill switch close to the platform to
stop the machine, this could stop the rotation to minimize continued
wrap. More importantly, if the unit had been equipped with a "slip
clutch," it could have been rotated in reverse to release
Recommendation #4: Construct a horizontal handrail from the top of the stair railing to the edge of the pug mill.
Discussion: The pug mill operator/monitor must climb five
stairs to reach the platform. Along the approximately threefootwide
stairs on the left and right are hand rails for the operator to
use while ascending and descending the stairs. At the top of the
stairs, along the right side, is a guardrail to prevent the operator
from falling off. On the left, the railing terminates at the stairs.
Further to the left, about three and a half feet from the top
of the stair railing, is the side of the pug mill, along which
the rotating shaft runs at foot level. There is a gap between
the top of the left stair railing and the side of the pug mill.
An operator who reaches the top of the stairs could lose his/her
balance, reach for the expected hand rail, find none, and fall
onto the rotating shaft. If the open space between the top of
the stairs and the pug mill were protected with a stationary bar,
this would offer a place to regain balance once on the surface
of the platform.
Recommendation #5: Employers should instruct employees to wear snugfitting clothing to minimize the chances for loose clothing to get caught in moving parts.
Discussion: In this case, the victim was wearing a heavy,
loosefitting overcoat which may have become caught on the
rotating coupling. Snugfitting clothing might have limited
the possibility of the clothing getting caught.
1 Competent Person: One who is capable of identifying
existing and predictable hazards in the surroundings or working
conditions which are unsanitary, hazardous, or dangerous, or dangerous
to employees, and who has the authority to prompt corrective measures
to eliminate them.
U.S Department of Labor, OSHA, Code of Federal Regulations, Labor
29 CFR 1910.219 (i) (2).