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T/V Exxon Valdez

The Alyeska Pipeline Service Company was immediately notified of the incident and sent a
tug to the site to assist in stabilizing the vessel.  At the time of the incident, the
Alyeska spill response barge was out of service being re-outfitted.  It arrived on scene
by 1500 on 24 March.  Alyeska was overwhelmed by the magnitude of the incident; by March
25, Exxon had assumed full responsibility for the spill and cleanup effort.\\Deployment of
boom around the vessel was complete within 35 hours of the grounding.  Exxon conducted
successful dispersant test applications on March 25 and 26 and was granted permission on
March 26 to apply dispersants to the oil slick.  Due to the large storm that began the
evening of March 26, much of the oil turned into mousse.  As dispersants aren't generally
able to dissipate oil in the form of mousse, it was no longer practical to use dispersants
on floating oil during this response.\\On the evening of March 25, a test in-situ burn of
oil on water was conducted.  Approximately 15,000 to 30,000 gallons of oil were collected
using 3M Fire Boom towed behind two fishing vessels in a U-shaped configuration, and
ignited.  The oil burned for a total of 75 minutes and was reduced to approximately 300
gallons of residue that could be collected easily.  It was estimated that the efficiency
of this test burn was 98 per cent or better. Again, continued in-situ burning was not
possible because of the change in the oil's state after the storm of March 26.  \\Five
dispersant trials took place between March 25 and March 28.  Corexit 9527 was used for the
trials.  Four of the tests used C-130 aircraft with ADDS packs, and one test was applied
from a DC-6 aircraft.   By March 29 the Regional Response Team (RRT) decided that
dispersants were no longer feasible.\\Because there was not enough equipment to protect
all the shorelines that could be impacted, Federal, state and local agencies collaborated
to establish shoreline protection priorities.  The agencies decided that fish hatcheries
and salmon streams had the highest priority; accordingly, containment booms were deployed
to protect these areas. Five fish hatcheries in Prince William Sound and two in the Gulf
of Alaska were boomed, with the largest amount of  boom deployed at the Sawmill Bay
hatchery in Prince William Sound.  On April 15, the Sawmill Bay hatchery was boomed with
30,500 feet of sorbent boom and 28,600 feet of containment boom in multiple layers.  As
many as 15 to 20 boats were used daily for tending the boom and oil recovery by towing
sorbent boom.  Overall, the deflection of oil from the hatcheries was very successful.\\At
the height of containment efforts, it is estimated that a total of 100 miles of boom was
deployed.  Almost all the types of boom available on the market were used and tested
during the spill response. \\Due to the size of the spill, it was necessary to employ
inexperienced workers to deploy and tend booms, and this led to some boom being
incorrectly used or handled, and sometimes damaged.  Some boom sank because of improper
deployment, infrequent tending, or leakage and/or inadequacy in the buoyancy system.
Other problems included fabric tears in boom due to debris, and tearing at anchorage
points from wave action.  In some cases, ballast chains were ripped off during boom
recovery if the boom was lifted by the chain.  One estimate suggests that 50 per cent of
the damage to larger boom came during boom recovery.  For self-inflating booms, it was
important to keep the inflation valves above the water during deployment so that the boom
did not become filled with water and have to be replaced.  \\Since most of the containment
boom was in  50 to 100 feet long sections, several lengths of boom usually needed to be
connected for deployment.  When several types of boom were used in one operation, there
were often problems with incompatible connectors between different types of boom.  Bailing
wire and other adaptations were used in the field for these situations.  A universal type
of connector (ASTM connector) came with some booms, but these were difficult to handle and
hook up at sea and were hard to open once they had been submerged in cold water.  Booms to
be re-used were hand cleaned early on in the spill, and as the spill progressed were
cleaned in one of the two barges with mechanical washing facilities.\\To contain oil on
the open water, containment boom was towed between two vessels (usually fishing boats) to
surround the oil and then the two ends of the boom were drawn together to close the loop
and await collection by a skimmer.  \\Aerial surveillance was used to direct the
deployment of booms and skimmers for open water oil recovery.  Visual overflight
observations as well as ultraviolet/infrared (UV/IR) surveys were used by the USCG and
Exxon to track the floating oil.  Satellite imagery was also tested as a method to track
oil but was not very useful because of the infrequency of satellite passes over Prince
William Sound (every 7 to 8 days), cloud cover, and lengthy turn around time for results.
\\The primary means of open water oil recovery was with skimmers.  In general, most
skimmers became less effective once the oil had spread, emulsified and mixed with debris.
To save time, it was most practical to keep skimmer offloading equipment and oil storage
barges near the skimmers.\\Weir skimmers were useful for collecting fresh oil that was
present in a thick layer on the water.  As the oil became weathered and laden with debris,
however, it was the simple weir skimmers that were the first to clog.  Some of the larger
weir skimmers had auger pumps with cutters for chopping debris and were able to collect
oil for a longer time than the simple models.  \\Oleophilic disc skimmers also worked well
while the oil was fairly fresh.  Once the oil became viscous and associated with debris,
these skimmers were not very effective.\\An Egmolap brand paddle belt skimmer (Egmolap II)
was used and was effective for heavy mousse and debris.  It collected very little water
under light sea conditions.  A different paddle belt skimmer that was supplied by the
Canadian Coast Guard clogged easily when working with viscous oil.\\When using rope mop
skimmers, it was important to maintain the smallest angle possible when lifting the
skimmer out of the water, so that the oil did not run down the mop and back into the
water.  In situations where the oil was viscous, it was useful to cut down the diameter of
the mop from nine to six inches and inject diesel oil into the ringers as the mop was
being rung out.\\The most used skimmers during the response were the Marco sorbent
lifting-belt skimmers that were supplied by the U. S. Navy.  Once oil became viscous, the
sorbent part of the skimmer was removed and the conveyor belt alone was sufficient to pull
the oil up the ramp.  The pump that came with the skimmer had difficulty offloading
viscous oil, so that other vacuum equipment was used to unload the collected oil.  The
Marco skimmers were generally not used close to shore because they drawbetween three and
four feet.  In general, the paddle belt and rope mop skimmers were the most useful for
recovery of oil from the shoreline.  The skimmers were placed on self-propelled barges
with a shallow draft.\\Sorbents were used to recover oil in cases where mechanical means
were less practical.  The drawback to sorbents was that they were labor intensive and
generated additional solid waste.  Sorbent boom was used to collect sheen between primary
and secondary layers of offshore boom, and to collect sheen released from the beach during
tidal flooding.  Pompoms were useful for picking up small amounts of weathered oil.
Towing of sorbent boom in a zigzag or circular fashion behind a boat was used to collect
oil and was more efficient than towing the boom in a straight line.  Sorbent booms made of
rolled pads were more effective than booms made of individual particles because these
absorbed less water and were stronger, and did not break into many small particles if they
came apart.\\During the Exxon Valdez spill response, a hopper dredge was used to collect
oil for the first time in the United States.  The oil was gathered using a containment
boom, and the draghead of the dredge was placed under the boom below the oil surface.  The
oil was then sucked up and placed in storage containers on the dredge.  The drawbacks to
using the dredge were that it recovers large amounts of water with the oil and must be
used offshore because of its deep draft.\\To transfer the recovered oil, water, and debris
mixture from the skimmers to temporary storage containers, vacuum equipment and positive-
displacement pumps were used.  Vacuum trucks on barges or air-conveyers were most useful
when used with an open-ended suction hose with a diameter of 6 to 8 inches.  \\Early on in
the response, storage space for recovered oil was in short supply.  To combat the storage
space problem, water was decanted from skimmers or tanks into a boomed area before
offloading.  As a result, the remaining viscous oil mixture was difficult to offload, the
process sometimes taking up to 6 to 8 hours.  High-capacity skimmer offloading pumps, in
particular grain pumps, were the most useful in transferring viscous oil.\\Because
recovery equipment was in near constant use, several vessels were set up to perform field
repairs and conduct preventive maintenance.\\The oil remaining on the Exxon Valdez, was
completely offloaded by the end of the first week in April 1989.  After offloading
operations were completed, the tanker was towed to a location 25 miles from Naked Island
in Prince William Sound for temporary repairs.  Later in the summer of 1989, the vessel
was brought to California for further repairs.\\Shoreline assessment was a prerequisite
for the implementation of any beach cleanup.  Assessment provided geomorphological,
biological, archaeological and oiling information that was used for the development of
site specific treatment strategies.  Cleanup operations were scheduled around specific
activities such as seal haulout activity, seal pupping, eagle nesting, fish spawning,
fishing seasons, and other significant events as much as possible.\\In 1989, hoses
spraying seawater were used to flush oil from shorelines. The released oil was then
trapped with offshore boom, and removed using skimmers, vacuum trucks (useful for thick
layers of oil) and boom (sorbent, snare, pompoms).  For hard to reach areas, or locations
with weathered oil, heated seawater was used to flush oil from the shoreline.  \\Converted
vessels and barges were used for beach washing operations.  It would take several days to
outfit a conventional barge with the equipment needed to heat and pump the water.  Smaller
vessels that were used for beach washing early in the spill were re-outfitted for
bioremediation later in the response.\\Along with the large scale beach washing, manual
cleanup, raking and tilling the beaches, oily debris pickup, enhanced bioremediation and
spot washing were used to cleanup the oil.  In some locations, oil was thick enough to be
picked up with shovels and buckets.  In addition, mechanical methods were used on a few
sites, including the use of bulldozers to relocate or remove the contaminated beach
surfaces.  Mechanical rock washing machines, which were manufactured for the spill, were
not used to clean contaminated rocks and return them to the beach. \\Oiled storm berm was
mechanically relocated in some cases so that these areas, which normally would not receive
much wave action, would be more exposed and cleaned by natural processes.  If the oiling
in the berm was significant or persistent it was tilled to free the oil or washed to
optimize the cleaning.  Recommendations were made to restrict the movement of berm to the
upper third of the beach to ensure its return to the original location.\\Beach
applications of dispersants were tried in several locations.  Corexit 7664 was applied on
Ingot Island, followed by a warm water wash. No significant change in oil cover or the
physical state of the oil was observed as a result of the treatment. Some ecological
impacts were observed in the treated areas.   It appeared that the effects were largely
due to the intensive washing more that the use of Corexit 7664, and were evident in
intertidal epibenthic macrobiota.\\In addition, the dispersant BP1100X was applied to a
test area on Knight Island.  Toxicology studies indicated that the upper and lower
intertidal biota were different from pre-application communities the day after dispersant
application, and returned to pre-treatment levels after seven days.  \\Exxon also tested
the dispersant Corexit 9580 in Prince William Sound.  The decision to approve a large
scale test of Corexit 9580 in August was reached after an extensive program aimed at
evaluating shoreline cleaning technologies.  The monitoring program addressed three major
issues:  migration of oil and Corexit in shoreline sediments, the migration of sediments
and oil in the nearshore environments, and the migration of oil in the water column, each
being evaluated in the monitoring program.   The dispersant's effectiveness and impact
were then compared to mechanical shoreline cleanup methods, and this information was used
to determine whether Corexit 9580 should be used for shoreline treatment.  The Research
and Development Committee evaluating the proposal for dispersant use recommended against
broad-scale application of the product because tests had not adequately demonstrated that
removal and recovery efficiency outweighed possible adverse effects.  The committee
recommended using Corexit only on Smith Island, subject to continued review of the
effectiveness of recovery procedures by on-scene monitors.\\In May of 1989, the
Environmental Protection Agency (EPA) and Exxon conducted bioremediation trials at two
test sites on Knight Island in Prince William Sound.  On the basis of these tests and
other trials later in the summer, Exxon recommended the use of the bioremediation
enhancement agents, Inipol (Inipol EAP22--manufactured by Elf Aquitaine of France) and
Customblen (Customblen 28-8-0 --manufactured by Sierra Chemicals of California), and
subsequently treated over 70 miles of shoreline in Prince William Sound with these
agents.\\Past scientific research had determined that sufficient numbers of hydrocarbon
degrading bacteria existed naturally in Alaska.  It was decided that the limiting factor
in enhancing petroleum hydrocarbon degradation was the availability of nitrogen and
phosphorus for the indigenous bacteria.  As a result, bioremediation trials focused on
agents that were basically "fertilizers", and contained no living microorganisms.
Considerations in the selection of bioremediation agents included ease of application, the
possibility of causing algal blooms and eutrophication in areas where nitrogen/phosphorus
concentrations would remain elevated (such as sheltered bays and estuaries), the flushing
of nutrients from the beach soon after application due to tidal action, and the possible
toxicity associated with concentrations of nitrogen based compounds (such as
ammonia).\\Winter monitoring of the effects of bioremediation consisted of surveys of more
than 20 beaches in Prince William Sound and the Gulf of Alaska.  These studies determined
that oil degradation had been enhanced on the shorelines monitored, but some debate
existed over whether bioremediation was solely, or even largely, responsible.\\Cleanup
operations in 1989 ceased by the end of September.  All parties involved in the response
agreed that continuation of cleanup into the Alaskan winter would jeopardize the safety of
cleanup crews.  In addition, it was speculated that the winter storms in Alaska could
significantly remove oil from shorelines, including sub-surface oil.  By the end of the
1989 cleanup, more than 25,000 tons of oiled waste and several hundred thousand barrels of
oil/liquid waste were collected and disposed of in landfills.\\Cleanup in 1990 began in
April and ended in September.  Surveys in the spring of 1990 showed that oiling conditions
had been reduced or changed over the winter.  Surface oil in 1990 was significantly
weathered but sub-surface oil was relatively fresh in some locat

ons.   Cleanup techniques in 1990 focused more on manual methods of treatment such as hand
wiping and spot washing as well as bioremediation.  Mechanical equipment was used on a few
sites.  \\Bioremediation was more extensive in 1990, with 378 of the 587 shoreline
segments treated that year receiving bioremediation application.  In general, Inipol was
applied in cases where surface oiling existed and Customblen slow release pellets were
preferred for treating beaches with sub-surface oiling.  Generally, beaches were given one
to three treatments over several months.  Concern over the possible toxicity of Inipol led
to recommendations for application of only Customblen on some sites.\\By the spring of
1991, the scope of the cleanup effort was greatly reduced.  Manual cleanup,
bioremediation, and very limited use of mechanical equipment were employed.  Cleanup took
place from May of 1991 through July of 1991.  \\An important observation that resulted
from the Exxon Valdez oil spill was that natural cleaning pr

ocesses, on both sheltered and exposed beaches, were in many cases very effective at
degrading oil.  It took longer for some sections of shoreline to recover from some of the
invasive cleaning methods (hot water flushing in particular) than from the oiling itself.