On January 8, 2002, at the Los Alamos National Laboratory, a
reaction vessel containing chlorine dioxide (ClO2) exploded inside a
chemical hood while chemists were conducting an experiment to develop a method
for synthesizing chlorine dioxide in a form that would allow safe storage and
transport. Chlorine dioxide is known to
be highly reactive and sensitive to multiple types of initiation energies, such
as temperature, pressure, static electricity, contaminants and sunlight. One chemist received minor scratches, and
the other was uninjured. (ORPS Report
ALO-LA-LANL-CHEMLASER-2002-0001)
During the experiment, one of the chemists monitored the
pressure and temperature of the pressure vessel (ClO2 generator),
which was certified for 3,000 pounds per square inch. He noticed the temperature rising from the ideal temperature
range of 40˚C to 80˚C. At
that time, he called to the other chemist and told him to get out of the
room. He then stepped out the door next
to the chemical hood and isolated the chlorine gas supply line. At that time, the experiment exploded,
destroying the vessel and hood, and severely damaging other equipment in close
proximity. At that point, the chemists
evacuated the building and called 911.
They were transported to Occupational Medicine, where they were evaluated
and released without restriction. As a
precaution, the Emergency Management and Response Incident Command supervised a
controlled release of all non-essential personnel from the adjacent operations
area.
DOE has directed the Laboratory to conduct an accident
investigation. An update of this event
and lessons learned will be published in the OE Summary after the final
investigation report has been issued.
On October 8, 2001, in a laboratory at the Oak Ridge
National Laboratory (ORNL) West Complex, sealed glass tubes containing ferric
chloride and hydrochloric acid exploded while being heated inside a microwave
oven. The explosion broke the glass
turntable in the microwave oven, opened the oven door, and released glassware
fragments and chemicals outside the oven.
Researchers for the experiment were standing near the oven while this
occurred; however, no one was injured or contaminated. The contractor reported this as a near miss
occurrence. (ORPS Report ORO--ORNL-X10WEST-2001-0012).
The experiment's principal researcher purchased a
household microwave oven from a local department store for the experiment. The conventional oven he had used previously
took several hours to heat the chemicals, and he hoped that a microwave oven
would reduce the heating time to a few minutes. While the operating manual for the household microwave oven
clearly cautioned against heating closed containers and chemicals, the
researcher ignored these warnings. In
preparing samples to heat in the microwave oven, he placed one-half milliliter
of a ferric chloride and hydrochloric acid solution into each of four thin
Pyrex® tubes that were four to five inches long and heat-sealed the
ends. The researcher believed that the
small amount of liquid in the glass tubes would not cause pressures to exceed
the 400 to 500 pounds per square inch pressure-retaining capability of the
tubes. However, he did not perform a
design analysis and failed to enlist the aid of a subject matter expert to
verify his assumption. Subsequent
calculations showed that he grossly underestimated the air space needed to
accommodate the expansion of the solution from a liquid to a gas.
The researcher placed the tubes inside the microwave
oven, set the oven at 60 percent power for two minutes, and waited beside the
microwave oven while an assistant stood in front. The tubes exploded after about one minute, opening the oven door
and splattering liquid chemical about 1 foot, which fortunately was not far
enough to hit the researchers. Glass
stained with ferric chloride landed near the assistant, but he was not
injured. Both researchers were wearing
safety glasses.
A subsequent investigation of this occurrence found that
not only had the use of a microwave oven in this experiment not been subject to
a design review by subject matter experts, but neither had the previous use of
a conventional oven. The investigators
determined that the root causes of the event were deficient work planning and
inadequate hazards analysis.
During 1999, bioassay laboratories at the Savannah River
Site experienced three separate explosions of sealed vessels inside microwave
ovens. During the most recent
explosion, on December 13, 1999, the sealed ceramic container of a fecal sample
burst, breaking the glass turntable in the microwave oven and opening the oven
door. A subsequent investigation found
that an electrical short in the pressure transducer prevented accurate
monitoring of the vessel's pressure, and that the vessel's rupture disk had
failed to function. The microwave oven was designed for laboratory use and had
a safety device that restricted the opening of the door to a few inches. Although glass and other material fell onto
the laboratory floor, the restricted door movement kept workers nearby from
being injured. (ORPS Report SR--WSRC-LTA-1999-0039, OE
Summary 2000-1).
These occurrences show that heating sealed containers or
chemicals inside microwave ovens is hazardous.
The ORNL occurrence illustrates the importance of hazard analyses and
design reviews for laboratory experiments.
Personnel selecting and using laboratory equipment should consider the
hazards analyzed as well as the manufacturer's recommendations.
KEYWORDS: Microwave oven, laboratory, explosion
ISM CORE
FUNCTIONS: Analyze the Hazards, Develop and Implement Hazard Controls
On December 5,
2001, at the Fernald Environmental Management Project (FEMP), two subcontractor
equipment operators were positioning and preparing a light tower (portable
floodlight) for use when the
mast fell, resulting in a head injury to one of the operators. The equipment operator received a glancing
blow that knocked him to the ground and resulted in a laceration of the scalp. He did not lose consciousness, and was taken
to an offsite hospital for evaluation and treatment. The operator was released by the hospital and returned to finish
his shift. Neither equipment operator
was wearing a hard hat, which was required by the work plan. The final ORPS Report on this event was filed
on January 23, 2002. (ORPS
Report OH-FN-FFI-FEMP-2001-0017)
The equipment operators were positioning a TEREX®
Amida 3-section, telescoping light
tower to provide additional lighting for a parking area. This particular model (TX3000) uses a
single-winch system to raise and lower the mast vertically and
horizontally. A spring-loaded locking
device, consisting of a sliding bar that is tapered on one side, can be locked
in the engaged position by a locking pin.
This allows a single winch to perform two operations: (1) telescoping the mast sections
vertically, and (2) raising and lowering the mast sections (in the retracted
position) from the horizontal transport position to the vertical position. Figure 1 shows the light tower in the
lowered horizontal position, and Figure 2 shows a typical light tower in
the fully raised position.
After
raising the mast, the equipment operators noticed that one lamp was aimed
skyward and required adjustment. One of
the operators turned the crank to lower the mast vertically until the sections
of the mast were seated. He then
inserted the spring-loaded lock pin to secure the mast sections in place and
released the vertical lock pin to allow the mast to be lowered
horizontally. When the mast was at
approximately a 15-degree angle above horizontal, it suddenly fell to the
horizontal position and extended approximately 42 inches. The other operator, who was standing outside
the expected fall area of the mast, was struck on the top right side of his
head and was knocked to the ground. The
operator who lowered the mast immediately began to administer first aid to his
co-worker, who suffered a scalp laceration approximately three inches in
length.
The Site Project Safety and Health Manager
directed that the position of the fallen light mast not be altered until
further details about the incident were known, that the supplier or
manufacturer of the light tower be contacted to see if there were any known
problems related to the mast, and that all light towers at FEMP be secured
immediately.
A site investigation indicated that the direct cause of
the injury was failure to follow procedure because the equipment operators were
not wearing hard hats when the injury occurred. Although the work area does not require the use of personal
protective equipment (PPE), the project-specific safe work plans and safety
programs did require the use of proper PPE, including hard hats, when working
on equipment.
Additionally, the equipment operator who was struck was
standing in front of the lowering mast, although outside the radius of its
retracted configuration. The
project-specific safe work plan directs personnel to perform work from outside
the normal travel range of the part or attachment.
A contributing cause of this occurrence was
?inattention to detail? because investigators determined that the sliding bar
was not fully engaged and was not locked into the inner sections when the mast
was lowered. It was noted that the
manufacturer's diagram on the mast does not clearly depict the fully locked bar
configuration for the safe lowering of the mast. Also, this was the first time the equipment operator had operated
this type (single-winch) of light tower, and he did not consider it necessary
to refer to the operator's manual.
Figure 3 illustrates the locking mechanism.
Investigators determined the root cause of this occurrence
was ?inadequate or defective design.? A
manufacturer's design engineer met with subcontractor and Fluor Fernald
personnel to evaluate the incident. A
replication of the sequence of events, as described by both equipment
operators, resulted in a duplication of the occurrence. The design engineer could not confirm the
designed configuration of an alignment tab, but did acknowledge that the tab
appeared to have been bent and that the function of the safety pin and
retaining washer could easily be defeated.
He added that he believed that the mast spring-loaded locking device
design was not intended to allow as much freedom of movement as could be seen
with this sliding bar. The light tower
involved in this incident, as well as five other light towers by the same
manufacturer that were on site, allowed the spring-loaded locking bar to be
disengaged and turned 90 degrees, even with the locking pin inserted behind the
retaining washer on the spring-loaded locking bar.
As a result of the investigation, all single-winch light
towers were removed from service at FEMP, and will be replaced with
double-winch units from a different manufacturer. The two-winch units are considered to be safer than single-winch
light towers. Safety precautions were
also developed for all Fernald personnel involved in using light towers. Additionally, hardhat requirement labels
will be affixed to all light towers site-wide.
It is suggested that personnel at DOE facilities review the use of
single-winch light towers in service at their sites to ensure that similar
accidents do not occur.
KEYWORDS: Light tower, portable
floodlights, injury, defective design, procedure, inattention to detail
ISM CORE FUNCTIONS: Analyze the Hazards, Develop
and Implement Hazard Controls, Perform Work Within Controls
On November 12, 2001 at the Rocky Flats Environmental
Technology Site, a demolition crew destroyed a guard tower using an explosive
device. The tower fell immediately, and
debris rolled onto a 480-volt junction box containing wiring that fed the
Perimeter Security Zone lighting system.
A photoelectric sensor that was designed to de-energize the lights
during daylight hours controlled the wiring inside the junction box. A final ORPS report for this event was filed
on December 21, 2001. (ORPS Report RFO--KHLL-FACOPS-2001-0006)
Shortly after detonation, a front-end loader was used to
move the tower rubble so that the excavation crew could visually observe the
scene and ensure that all explosive charges had been detonated. The junction box, which protruded slightly
above ground level, was damaged during the clearing operation, causing the conductors
to become exposed. Several days later,
a team of excavation specialists preparing for removal of the tower foundation
discovered that the junction box had been damaged, and observed several exposed
wires. The specialists checked the
sites where two other towers had been demolished on the same day, and no other
damaged electrical equipment was found.
The 480-volt wires were exposed from about noon on Saturday
until Monday morning, when the condition was discovered. A photoelectric sensor, designed to
de-energize the lights during daylight hours, controlled the wiring inside the
junction box. Because of the remote
location of the tower and the time of day that the demolition took place, the
potential for electric shock was low.
However, the photoelectric sensor represented the only remaining barrier
to an electric shock event after other barriers had been compromised.
The direct cause of this event was personnel error ?
inattention to detail. The junction box
containing wiring for the perimeter lighting system was originally determined
to be out of the way of the designated fall path and at a sufficient distance
away from the structure that it would not pose a hazard when the tower
fell. Therefore, the electrical hazard
was not addressed in the activity hazard analysis. Project management did not anticipate or make allowances for a
subsequent field change in the work plan (described below) that caused the
junction box to be in the fall path of the tower debris.
The contributing cause was determined to be inadequate
administrative control. The demolition
contractor requested a change to the plan that would cause the tower to fall at
a location 90 degrees different than originally proposed due to irregularities
in the structure of the tower.
Following a document review conducted in the field, the project manager
approved the change, and work commenced to detonate the tower. The change in work activities presented
another opportunity to perform a more thorough review and analyze the previously
unrecognized hazard.
The root cause of the event was determined to be a
deficiency in work organization and planning related to the failure to include
the junction box in the recognized set of hazards during pre-job planning. Work planners need to ensure that adequate
controls are in place and require a thorough review of all work activities and
anticipated hazards.
Work planning documents and proposed job activities must be
carefully evaluated for hazards that may be introduced when a level of
uncertainty exists. Because demolition
work using explosives had not previously been performed at the site, the
increased level of uncertainty should have led to a more thorough job
review. Failure to perform adequate
pre-job planning in a rapidly evolving environment can result in unsafe
conditions. Work should not commence
until there is a thorough understanding of the hazards involved and
corresponding controls have been implemented.
KEYWORDS: Energized circuit, electrical,
junction box
ISM CORE
FUNCTIONS: Analyze the Hazards, Develop and Implement Hazard Controls
On November 5, 2001 at the Portsmouth Gaseous Diffusion
Plant, a safety inspector observed two subcontractor workers performing
overhead activities from an elevation of about 10 to 12 feet without fall
protection. One worker had used a
ladder to access a pipe chase, stepped from the ladder onto the piping, and was
not tied off or wearing a safety harness.
The inspectors terminated the work and initiated an investigation into
the noncompliance. No one was injured
in this event. (ORPS Report ORO--BJC-PORTENVRES-2001-0017)
Two subcontractor workers were installing an electrical
connection in an existing facility without engineering drawings to specify location
and configuration. The work package
contained a scope of work description and an activity hazard analysis. A pre-job safety briefing was held. The hazard analysis did not address the need
for fall protection, as the workers had a lift platform available from which to
perform overhead activities. During the
course of the work, the lift broke down.
The workers were temporarily sent away to complete other jobs and
subsequently returned to the work site.
Their supervisor was working with another crew in a different building
at the time, and also had jobs and crews in other buildings.
Because the workers were left to rely on skill-of-the-craft
(instead of engineering drawings) to perform the work, they decided to use a
ladder to reach the pipe chase and then roll from the ladder onto the
piping. There wasn?t enough space to
stand above the pipes, nor was there an approved tie-off point for a
lanyard. The worker who climbed onto
the pipe chase chose to lie on his back to make the electrical connection. The worker commented that it had been common
practice (without fall protection) to work in such a fashion while working for
the United States Enrichment Corporation, where both workers had received fall
protection training.
After the incident, both subcontractor employees were
given a remedial course in fall protection (Lesson Plan # 11915, based on
BJC-EH-2003, Rev. 0, Elevated Working
Surfaces and Fall Protection, and Wastren's procedure SH-A-2003, Elevated Work/ Fall Prevention, Rev.
0). The lesson plan notes that a
harness and lanyard should be used when working at elevations greater than 15½
feet. This height appears to be
inconsistent with the height requirement stated in the Occupational Safety and
Health Administration (OSHA) standards, 29 Code of Federal Regulations
(CFR). For example, 29 CFR 1926.501, Duty to Have Fall Protection, requires
employers to determine that walking/working surfaces have the strength and
structural integrity to safely support their employees. The regulation further states, that each
employee on a walking/working surface with an unprotected side or edge that is
6 feet or more above a lower level must be protected from falling by a
guardrail system, a safety net system, or a personal fall-arrest system.
The workers claimed that the type of fall protection
available to them would have allowed them to hit the floor had they used it
because they were 12 feet above the floor.
The comment was made in the event critique that they could have wrapped
the lanyard around the pipes to take out some of the slack, however that was
not an approved tie-off for this job.
In fact there were no approved tie-off points.
Skill-of-the-craft latitude should not be given if the
required safety equipment specified in the work package becomes unavailable
during the work activity, as this could significantly impact the safety
precautions required during the performance of the work. The activity hazard analysis was
insufficient for the scope of work. In
addition, the supervisor was overseeing work in five different buildings at the
same time, and could not adequately advise the workers.
KEYWORDS: Fall protection, work packages
ISM CORE FUNCTIONS: Analyze the Hazards, Develop and Implement Hazard Controls, Perform
Work within Controls
On January 4, 2002, DOE issued a Preliminary Notice of
Violation (PNOV) against Fluor Fernald, Inc., contractor of the Fernald
Environmental Management Project (FEMP).
This action is a result of a series of procedural nuclear safety
violations of the Occupational Radiation Protection Rule (10 CFR 835) (NTS Reports
NTS-OH-FN-FFI-FEMP-2000-0005 & -0006) and the Quality Assurance Rule
(10 CFR 830.120) (NTS
Reports NTS-OH-FN-FFI-FEMP-2001-0003 & -0004) at the Fernald Waste
Pits Remedial Action Project (WPRAP). The deficiencies were
brought to light from DOE's evaluation of several problems and events occurring
during calendar years 2000 and 2001 and from a recent DOE-FEMP review.
Section I of the PNOV relates to the elevated airborne
radioactivity levels at the WPRAP T321 trailer. The violation includes multiple radiological program deficiencies
associated with the event; namely, the lack of appropriate air monitoring and
the failure to maintain worker exposures As Low As Reasonably Achievable
(ALARA). Subsequent to the startup of
thermal dryer operations at WPRAP, no effective design features or
administrative controls were instituted to limit radiation exposure from the
inhalation of thorium-230 by personnel in the trailer. As a result of these deficiencies, 23
personnel received unplanned and unmonitored exposures ranging from
approximately 30 to 330 millirem for the period December 1999 through August
2000. These violations constituted a
Severity Level II problem with a civil penalty of $27,500.
Section II of the PNOV contains a violation describing
deficiencies in the quality improvement area. Specifically, examples were noted
in which Fluor Fernald processes were not effective in controlling and
resolving identified deficiencies in a timely manner. These examples include (1) the failure to ensure that issues
identified in the Conduct of Operations Monitor Reports were placed in an
appropriate corrective action process; (2) the failure to correct deficiencies
initially identified by Fluor Fernald relating to the operator training
program; and (3) the failure to take sufficient corrective actions following an
earlier WPRAP airborne radioactivity event to preclude or correct in a more
timely fashion the subsequent T321 problem.
These violations constituted a Severity Level II problem with a civil
penalty of $27,500.
No monetary mitigation in these civil penalties for timely
self-identification was provided to Fluor Fernald because the violations were
either long-standing in nature or identified by DOE. However, DOE recognized that Fluor Fernald promptly entered the
deficiencies into DOE's Noncompliance Tracking System (NTS) once they were
identified. DOE also recognized that
Fluor Fernald had proactively reported roll-up Conduct of Operations and
Radiological Control programmatic issues at WPRAP into the NTS earlier during
2001, and was undertaking corrective actions for those issues. Both fines were therefore reduced by 50
percent mitigation in recognition of Fluor Fernald's comprehensive and timely
corrective actions relative to the subject events once they were identified,
and in light of Fluor Fernald's historically strong Price-Anderson Amendments
Act (PAAA) performance with respect to the self-identification and correction
of regulatory issues.
These violations illustrate several lessons learned from a
management perspective with potentially significant impact on PAAA enforcement,
including:
?
The need for timely and aggressive action in addressing
identified deficiencies and precursor conditions, and
?
The need to ensure that short-term compensatory or
"workaround" measures instituted during startup are followed up with
appropriate longer-term measures.
Additionally, ALARA principles should be considered in the
preliminary design stage of facility modifications.
The Price-Anderson
Amendments Act of 1988 requires the Energy Department to undertake regulatory
enforcement actions against contractors for violations of its nuclear safety
requirements. The program is
implemented by the Office of Price-Anderson Enforcement. This action was taken with the support and
participation of DOE-FEMP, which will
ensure that the corrective actions are fully implemented. Additional details can be found on the
Internet at http://tis.eh.doe.gov/enforce.
KEYWORDS:
Enforcement, Price-Anderson Amendments Act, radiation monitoring,
training, corrective actions
ISM CORE FUNCTIONS: Analyze the Hazards, Develop and Implement Hazard Controls,
Perform Work within Controls
