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TESTIMONY OF
KEVIN YESKEY, MD
ACTING DIRECTOR
EMERGENCY
AND ENVIRONMENTAL HEALTH SERVICES NATIONAL
CENTER FOR ENVIRONMENTAL HEALTH CENTERS FOR
DISEASE CONTROL AND PREVENTION
BEFORE THE
HOUSE ARMED SERVICES COMMITTEEMILITARY
PROCUREMENT SUBCOMMITTEE
SEPTEMBER 21, 2000
Good morning. I am Dr. Kevin Yeskey, Acting Director of the
Emergency and Environmental Health Services Division of the
National Center for Environmental Health (NCEH), one of the
Centers within the Centers for Disease Control and Prevention
(CDC). I would like to thank the Committee for inviting me
here today to discuss CDC's Congressionally mandated public
health oversight role to the Department of Defense chemical
demilitarization program and specifically our investigation
of the agent release at Tooele, Utah. CDC provides independent
oversight of Department of Defense's lethal chemical agent
disposal facilities as a critical element of our role as a
public health service agency. Furthermore, I
would like to especially thank you, Chairman Hunter, for your
interest in ensuring the safe disposal of our nation's chemical
weapons stockpile.
CDC's Overall Chemical
Demilitarization Mission
As an extension of the U.S.
Department of Health and Human Services, CDC reviews all Department
of Defense (DOD) plans for destroying the nation's stockpile
of chemical weapons. CDC evaluates any selected technology
to ensure protection of the health and safety of the workers
and the surrounding community. Once the technology is selected
and implemented by DOD, CDC reviews facility design
provisions and operating procedures aimed at protecting the
workforce and surrounding communities.
During operations, CDC continues to monitor and inspect the
demilitarization facilities. Since air monitoring is
a critical element in detecting any possible agent release
incidents, CDC regularly examines air monitoring methods and
strategies, as well as the quality of the data from these
systems. Finally, to ensure local medical and emergency personnel
are prepared to respond to an incident involving chemical
agent, CDC provides consultation services to medical and emergency
personnel near storage sites and reviews their capabilities
to respond to lethal chemical agent-related emergencies. In
its Congressionally mandated public health oversight capacity,
CDC responded to the agent release at the Tooele Chemical
Demilitarization Facility to ensure that public health was
protected in this particular case and to help minimize risk
of further releases. This response
is in addition to CDC's regular and unannounced inspection
visits to the TCDF prior to May 8 that also are part of CDC's
role to protect the health of the public in communities near
chemical weapons demilitarization facilities.
CDC Role at the TOCDF
Incident
The Army notified CDC on May 9, 2000 of
a chemical agent release from the common stack of the incineration
plant at TOCDF. CDC immediately responded by dispatching
a team to conduct an independent investigation of the incident.
As part of the investigation, an initial assessment of the
impact of the agent release on public health was conducted
to ensure there was no danger to the workers or the surrounding
community. CDC found the release was at a non-harmful exposure
level, and consequently, no adverse health effects are anticipated.
CDC then immediately followed our initial assessment with
an in-depth analysis of the incident which is captured in
our technical investigation report. Our report concludes that
the TOCDF employees and the surrounding community were not
exposed to a level of agent that would cause any short- or
long-term adverse health effects from the release. However,
CDC found several issues that simultaneously contributed to
the release of sarin (GB) which should be addressed prior
to resuming plant operations. In order to protect workers
and the surrounding communities, CDC offers fifteen recommendations
to help reduce the probability of similar events and enhance
the utility of existing systems.
Objectives of CDC's Investigation
The overall objective of CDC's investigation was to provide
an understanding of the operational events surrounding the
release including the period after the release, evaluate the
accuracy and validity of the air monitoring data, evaluate
the potential impact on public health and provide recommendations
as to how to prevent similar incidences in the future.
Summary of Events and Findings
The CDC first reviewed the engineering data to develop a
chronology of the operational events before, during, and after
the agent release. In addition to reviewing the data, CDC
also interviewed key plant personnel and Army representatives
to discuss the operational events.
This is the sequence of events as determined by our investigation:
On May 8, 2000, the staff at TOCDF terminated M56 rocket
burns (incinerating the chemical agent in the rockets containing
GB) at approximately 4:00 pm because the deactivation furnace
system lower tipping gate (this is the gate that drops the
waste into the furnace) failed to close properly. At 8:10
pm the maintenance staff began the procedure to repair the
gate and to clean the feed chute. The staff also cleaned the
liquid agent strainer and placed the used strainer sock containing
about one pound of waste contaminated with agent GB on the
upper sliding gate of the feed chute. This waste is believed
to be the major source of agent involved in the release. The
maintenance staff completed their activities at 9:30 pm. High
airflow rates through the pollution abatement system resulted
in the scrubber fluid being drawn through the air flow meter
into the demister. This caused the exhaust gas flow meter
in the deactivation furnace pollution abatement system (the
final air cleaning provision) to fail, causing an automatic
shut-down of the burners. The plant operators attempted to
relight the burners at 11:26 pm at which time the air monitors
in the common stack went into alarm. The control room
supervisors acknowledged the alarm, however, they allowed
the control room operator to continue recovery efforts because
they believed that the furnace was free of agent.
However, after the pollution abatement system went into alarm
at 11:41 pm, the supervisor directed the operator to isolate
the furnace and the pollution abatement system.
Although the confirmational air monitoring samples had not
yet been analyzed, the control room supervisor, still believing
no agent was present, directed the operator to purge the deactivation
furnace and relight the burners to maintain the after-burner
temperature above 1000 degrees (the operating temperature
required by the Environmental Protection Agency). During the
second attempt to relight the burners at 12:28 am the air
monitors in the common exhaust stack again went into alarm,
although with lower agent level readings than in the first
episode. The supervisor again directed the operator to isolate
the furnace and pollution abatement system at 12:32 am.
In summary, the low deactivation furnace temperature from
the loss of the burners and high air flow rates allowed a
trace amount of GB agent to be released through the common
stack. This release ultimately occurred as a result of a combination
of unusual maintenance procedures, failure to recognize live
agent in the system, and malfunctioning equipment.
Air Monitoring Systems
The air quality is constantly
measured both inside and outside the facility. These monitors
detect any variation in the air quality and are specifically
set to alarm if any agent is present.
CDC reviewed the operational
status of both in-plant
and outside air monitoring systems before, during, and after
the release. The monitoring data, quality control data, and
appropriateness of responses and activities of monitoring
personnel were evaluated. The overall accuracy and validity
of the monitoring data were carefully determined. The documentation,
interpretation, and utilization of the monitoring results
were examined. CDC also compared the air monitoring data and
operational events to evaluate the chronological, spatial,
and operational compatibility and consistency of these data.
After careful
review of the air monitoring data, CDC determined that all
monitors functioned as designed in detecting agent and alerting
the workers. Furthermore, the air monitoring data
is consistent with the operational events leading to the release.
Potential Impact on Public
Health
The most critical element of
our investigation was to assess the potential public health
impact to determine if the estimated amount of GB released
was at a high enough level to harm the plant workers or the
citizens in the surrounding community.
GB is a volatile chemical warfare
agent, which makes it primarily an inhalation hazard. It is
toxicologically related to organophosphate insecticides, which
produce adverse effects on the nervous system by inhibiting
cholinesterase (ChE) enzyme activity. The route of exposure
of GB can include the eyes, respiratory tract, and skin. In
high concentrations of GB, exposure can lead to central nervous
system failure and ultimately death.
CDC collected the air monitoring
data, real-time meteorologic data, and the operational data
then applied this information using an accepted Environmental
Protection Agency (EPA)-approved dispersion model to characterize
the agent plume to evaluate the potential exposure to workers
and the general public. CDC used this dispersion model based
on the highest concentration taken from the air monitoring
data over a 30-minute period, which is approximately equal
to the duration of the two-phase event. Using this calculation,
the total agent release based on CDC's conservative model
and exposure analysis would be equivalent to 46 mg over the
entire release. CDC believes this to be a substantial
overestimation of the actual release amount, and it is therefore,
a very conservative figure to use for the examination of human
health implications.
Based upon the results of this
modeling and a 30-minute duration of the release, the model
predicted the maximum possible exposure to GB at ground level
was less than 1/10 of 1% (or 1/1000th) of the exposure one
would receive if exposed to the general population limit (GPL),
a limit considered to have no adverse health impacts. The
GPL set by the Department of Health and Human Services for
GB is .000003 mg/m3.
To evaluate the maximum possible
impact on the health of workers at TOCDF during the GB release,
the model was again run using worst-case parameters. Although
local meteorologic data indicated that downwash conditions
(wind speed and direction conditions that result in rapid
movement of stack gases to ground level near the plant) probably
would not have occurred during the release, the downwash option
was used to ensure a worst case scenario. Even with this most
conservative approach, estimated maximum agent concentrations
were well below the established concentration of GB for the
8-hour occupational exposure limits (OEL), a limit considered
to have no adverse health impacts for workers. The OEL set
by the Department of Human Health Services for GB is .0001
mg/m3. Considering potential exposure for
the entire release period, the maximum possible exposure was
less than 1% of the allowable concentration. In
addition, since the TOCDF workers masked early during the
release their exposure was far less than the amount used for
this analysis. In conclusion CDC determined there was no adverse
health impact on the workers or the surrounding community
based on the workers responding to the release by wearing
their masks, no reports of GB exposure symptoms, and results
of the conservative model.
Recommendations
Based on our investigation of the incident, CDC has offered
several recommendations to further improve the public health
and safety surrounding the plant operations, to improve the
performance and utility of the monitoring system, and improve
overall community safety. The details of our recommendations
may be found in CDC's Technical Report.
The incidents leading to the
release were so called "non-normal" procedures conducted during
abnormal plant conditions. The process for implementing an
"non-normal" procedure should be reviewed and additional training
provided as needed to ensure the personnel have the capability
to conduct the "non-normal" procedure. Additionally there
should be an evaluation of all "non-normal" procedures to
ensure they can be performed safely.
Once the air monitoring system
goes into alarm, the most qualified control room operators
should be controlling operations. Furthermore, even when plant
personnel do not believe agent is in the system, when an agent-related
alarm activates, the alarm should be considered valid until
it can be proven false. Once the alarm is activated, the control
room supervisor should make all decisions consistent with
guidelines from the Contingency Procedure for Agent Detected
in the Stack manual. The contingency procedures should
be reviewed and updated to reflect this incident.
Prior to the restart of plant
agent operations, CDC recommends a careful review and evaluation
of the entire system. Intensified investigation is needed
to identify and eliminate the source of false stack alarms.
All air monitors should be challenged and reviewed for quality
assurance. An engineering evaluation of the location and operation
of the flow meter should be conducted. The deactivation furnace
feed chute and related gates should be evaluated to optimize
proper functioning. Finally, all components of the deactivation
furnace system including the pollution abatement systems need
to be systematically examined to ensure proper functioning.
Since there is some question
regarding the notification policy during an agent release
incident and the current policy is unclear, the procedure
to ensure that Tooele County is informed in a timely manner
of potential and confirmed agent released should be reviewed
and clarified. In addition, the notification process for other
organizations with potential involvement following a release
should be reviewed.
Next Steps
CDC will continue to monitor
DOD's response to our recommendations and will assist in any
way possible to ensure these recommendations are addressed
to the intent and detail necessary to minimize the potential
for any future chemical agent release to the plant workers
and the surrounding community. CDC has participated
in public meetings and will continue to attend public meetings
in the State of Utah to address questions and comments from
the community members regarding our report. CDC believes our
independent investigation was diligent and when combined with
the State of Utah's report provides a comprehensive analysis
of the incident, addressing events leading to the release,
the response afterwards, and the necessary corrective actions
to prevent occurrence of future events. Additionally during
the week of August 7, 2000, CDC conducted an on site review
of the Army's implementation of our recommendations. Based
on our final assessments of TOCDF and the Emergency Operations
Center, CDC has determined that our recommendations are being
addressed and implemented. CDC will continue to closely
monitor the DOD as they implement their necessary actions
to ensure that TOCDF workers and the surrounding community
of TOCDF are protected from exposure
to chemical agent. As a public health service agency, we believe
that protecting the public's health is the number one priority
in the destruction of these chemical weapons. We will continue
to work with DoD, the State of Utah, and the local communities
to demilitarize our nation's stockpiled lethal chemical weapons
in the safest manner possible while reducing the inherent
risk of exposure from continued storage.
Thank you for the opportunity
to testify today. I am happy to answer any questions that
you may have.
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