|Oklahoma Case Report: 03-OK-034-01
A 27-year-old gas drilling rig worker died on May 23, 2003 from blunt
force trauma to the head, neck, and chest during a cleanout operation
at the well. At the time of the incident, the victim was working within
eight feet of the kelly on the drilling rig floor. Compressed air was
used to blow out the conductor pipe, but due to a lack of communication,
the compressor was turned on before the valves were prepared to control
the flow of debris out of the hole. The excess pressure caused the kelly
bushing, drillpipe slips, and debris to be blown out of the rotary table.
The victim was struck by these objects and was pronounced dead on arrival
to the hospital.
Oklahoma Fatality Assessment and Control Evaluation (OKFACE) investigators
concluded that to prevent similar occurrences, employers should:
- Develop, implement, and enforce comprehensive written practices and
procedures for all drilling operations.
- Monitor all job tasks to ensure that employees are not directly positioned
in areas that are subject to flying parts, debris, and other hazards.
- Ensure that all employees are trained properly and possess the skills
necessary to recognize and control hazards for all operations in which
- Develop and utilize a written emergency action plan and train employees
on site-specific emergency response plans.
A 27-year-old gas drilling rig worker died on May 23, 2003 from blunt
force trauma to the head, neck, and chest after he was struck by the kelly
bushing and drillpipe slips. OKFACE investigators reviewed the death certificate,
related local news articles, and reports from the sheriff's office, Medical
Examiner, Occupational Safety and Health Administration (OSHA),
and emergency medical services (EMS). Interviews were conducted with company
officials, including safety representatives, at the company headquarters
on August 19, 2003.
The drilling company that employed the decedent had been in business
for 33 years and, at the time of the incident, employed 140 individuals.
The victim had five years of experience in drilling operations and had
worked for this drilling company off and on over that five-year period.
However, during this time of employment, he had been working for the employer
for only three days. At the time of the incident, the decedent was part
of a five-person crew that was working at a gas well site, which had been
in operation for three days (Figure 1). The victim
was fatally injured during a cleanout operation. The cleanout process
is a normal part of drilling operations and involves blowing out mud,
water, and debris by pressurizing the well shaft with either air or liquid
as the standard cleaning media. The victim had performed the cleanout
process many times in the past.
The company did have a comprehensive written safety program in place
at the time of the incident. The victim had received formal company safety
training and informal on-the-job training specifically relating to cleanout
operations. Safety meetings were held regularly, and levels of training
were measured by employee testing and demonstration. Two of the five workers
at the site had recently joined the crew from other drilling companies;
however, they each had years of experience in oil and gas drilling.
|Figure 1. Oil Rig Diagram (not to
At the time of the incident, the rig floor and working surfaces were
level and dry; the weather was warm with light to no wind. The victim
was working with four other crew members on a gas drilling rig, wearing
the necessary personal protective equipment (e.g., steel toe boots, hard
hat, eye protection). Prior to the incident, the decedent was assigned
the task of driller and was asked to find the bottom of the conductor
hole with the kelly (Figure 2). The kelly is used
to transmit power (rotary motion) from the rotary table and kelly bushing
to the drillstring (Table 1). After unlatching the
brake handle, the driller allowed the kelly to free fall to the bottom.
The uncontrolled fall caused the kelly to become jammed with debris, such
as water, mud, and other material, that had collected in the conductor
hole since the time it was originally drilled for the well. As a result,
a cleanout operation became necessary. Cleanout procedures involving air
or mud drilling fluid are acceptable norms in the oil and gas drilling
industry; however, drilling fluid is more commonly used than compressed
Table 1. Helpful
||a large diameter hole, lined with pipe, that varies
in depth depending on the local geology; the hole where the crew starts
the top of the well; also called a starter hole
||a long square or hexagonal steel bar with a hole drilled
through the middle for a fluid path; goes through the kelly bushing,
which is driven by the rotary table
||an adapter that connects the kelly to the rotary table
||a revolving or spinning section of the drillfloor that
provides power to turn the drillstring
||a combination of tools (e.g., the drillpipe, the bottomhole
assembly, and other tools) used to make the drill bit turn at the
bottom of the wellbore
||a casing string usually put in the well first to prevent
the sides of the hole from caving into the wellbore
After the kelly became jammed, a senior driller was assigned to take
over the brake handle and kelly; however, the decedent remained approximately
eight feet away on the rig floor. A newly hired, yet experienced, derrickman
had the job of running the air compressor. While the drillers were switching
positions, the derrickman realized that he had not started that particular
type of compressor in quite some time and left the rig floor to seek help
from another driller onsite.
Figure 2. Kelly and Kelly Bushing
In normal cleanout operation procedures, certain valves are closed prior
to turning on the compressed air, which allows control over the flow of
debris out of the hole and into a catch pond. Once the valves are prepared,
the driller indicates to the derrickman that the area is ready for the compressed
air. At some point between the senior driller preparing for cleanout and
the derrickman leaving the floor to turn on the air compressor, there was
a lack of communication and the air compressor was activated without the
senior driller’s knowledge, prior to the prescribed valves being shut.
After starting the air compressor, the derrickman returned to the rig floor
and, as he walked to his next assignment, the rotary table erupted. The
pressure normally used to complete the cleanout work is a minimum of 20
pounds per square inch. Within minutes, the kelly had pressurized well beyond
this point to 150 pounds per square inch. The victim, who was still on the
rig floor in close proximity to the kelly, was also unaware that the air
compressor had been turned on. The compressed air, at full pressure with
no valves closed to control or direct the flow, blew the kelly bushing,
drillpipe slips, and debris out of the rotary table; all of which struck
and landed on the victim.
Figure 3. Diagram of Kelly,
Bushing, and Rotary Table
The victim was the only crew member injured by the flying debris and
equipment. The victim was pulled away from the hazardous area, laid down,
and kept calm. There was some initial confusion over whom to call for
help, which caused a lack of quick medical response. Apparently no emergency
numbers were posted on-site; although, a cell phone was available, there
may have been some trouble getting through. One of the crew members went
to the nearest farmhouse to find out how to call local EMS, while another
was sent out to the road to direct first responders. EMS arrived at the
scene approximately 30 minutes after the incident and loaded the victim
for transport to the hospital. The victim was pronounced dead on arrival
to the hospital, which was approximately 20 miles away.
Cause of Death
The Medical Examiner's report listed the cause of death as blunt force
trauma of the head, neck, and chest.
Back to Top
Recommendation # 1: Employers should develop, implement, and enforce
comprehensive written practices and procedures for all drilling operations.
Discussion: Employers should develop, implement, and enforce standard
operating practices and procedures for all drilling operations to safeguard
against unexpected energization or startup of equipment/machinery, or
hazardous energy release during servicing and maintenance. These written
practices and procedures should be reviewed at least annually. In this
incident, standard operating procedures for performing cleanout, and training
to those procedures, were needed to help monitor air and hydraulic pressure
and control pumps and compressors. Had a standard written operating procedure
been in place and complied with by the crew, this incident may have been
prevented. While using compressed air is a normal cleanout practice, the
area around the rotary table becomes highly hazardous during the procedure
and requires certain precautions, such as following each step in order,
knowing where debris will go before the air is started, and clearing crew
members from dangerous areas. With enforced, documented procedures, the
chances of inadvertent hazardous energy release are reduced.
Recommendation #2: Employers should monitor all job tasks to ensure that
employees are not directly positioned in areas that are subject to flying
parts, debris, and other hazards.
Discussion: The employer and designated site supervisors should
monitor the site for hazardous situations and non-compliance. Any deviations
from written job procedures or safety standards, or any unsafe situations
that arise from site-specific work, should be addressed by management
and corrected immediately. All employees should take steps to address
unsafe work procedures and to eliminate them by accepted means of control
or modification, including, but not limited to, engineering controls,
work practice controls, and the use of personal protective equipment.
Employees should be aware of how they are positioned at all times to avoid
standing, sitting, or working in hazardous zones.
Recommendation #3: Employers should ensure that all employees are trained
properly and possess the skills necessary to recognize and control hazards
for all operations in which they participate.
Discussion: Employees should be trained thoroughly and formally
on the standard operating procedures that are relevant to their duties
and assignments. In addition, employers should consider thorough skill
evaluations or screening for functional skills prior to hire or work assignment.
For operations, such as performing cleanout on a drilling rig, the potential
hazards of blowouts during the operation should be addressed, as well
as ways to minimize or eliminate the hazards. In addition, training should
emphasize the importance of establishing and maintaining good communication
between all crew members while performing all work procedures. Documentation
of the training should be kept on file with the company, and periodic
retraining of employees should be done. Retraining should always occur
when there are changes in the equipment, processes, or hazards present.
Oil and gas industries should consider consulting sources such as publications
from the International Association of Drilling Contractors (IADC; http://www.iadc.org/) (Link Updated 4/1/2013) and OSHA’s Oil and Gas Well Drilling and Servicing eTool
general_safety/general_safety.html) for information on safety and
Recommendation #4: Employers should develop and utilize a written emergency
action plan and should train employees on site-specific emergency response
Discussion: The emergency action plan should be in written form
and include all necessary steps to take when an emergency occurs. The
plan should contain steps for providing emergency first aid and cardiopulmonary
resuscitation (CPR), the phone numbers for all emergency providers and
appropriate company officials, and the proper documentation forms to complete
following an emergency. The plan should also address fire evacuation and
prevention, severe weather procedures, and workplace violence and safety.
Every employee should be trained annually on the company's emergency action
plan. Information should be provided on the scope, purpose, and application
of the plan. Site-specific information (e.g., severe weather shelters,
fire evacuation plan, location of nearest medical care facilities, and
pertinent contact phone numbers) should be given to or posted for employees
each time a rig is moved. Employees should know where copies of site-specific
plans are kept and who to notify if the plans are not readily available.
In addition, remote jobsites should have cell phones, two-way radios,
or other reliable means of quick communication in the event of an emergency.
- 29 CFR 1910.145 Specifications for Accident Prevention: Signs
- American Petroleum Institute: Occupational Safety for Oil and
Gas Well Drilling and Servicing Operations (API RP54).
- Freudenrich, Craig C. How Stuff Works: How Oil Drilling Works.
- Occupational Safety and Health Administration. Oil and Gas Drilling
and Servicing: The Potential Hazards of this Industry.
- Occupational Safety and Health Administration. Oil and Gas Well
Drilling and Servicing eTool. (https://www.osha.gov/SLTC/etools/oilandgas/general_safety/general_safety.html)
Oklahoma FACE Program
The Oklahoma Fatality Assessment and Control Evaluation (OKFACE) is an
occupational fatality surveillance project to determine the epidemiology
of all fatal work-related injuries and identify and recommend prevention
strategies. FACE is a research program of the National Institute for Occupational
Safety and Health (NIOSH), Division of Safety Research.
These fatality investigations serve to prevent fatal work-related injuries
in the future by studying the work environment, the worker, the task the
worker was performing, the tools the worker was using, the energy exchange
resulting in injury, and the role of management in controlling how these
To contact Oklahoma
State FACE program personnel regarding State-based FACE reports, please
use information listed on the Contact Sheet on the NIOSH FACE website.
Please contact In-house
FACE program personnel regarding In-house FACE reports and to gain
assistance when State-FACE program personnel cannot be reached.