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EXECUTIVE SUMMARY
Several states are considering regulations to control vapor emis-
sions from the loading and ballasting of tankships and tank barges
carrying liquids such as volatile hydrocarbons. These vapors, displaced
by entering cargo or ballast as vessel tanks are filled, totaled 56,600
metric tons in the United States in 1985. About 95 percent were from
crude oil and gasoline cargoes; two-thirds came from inland barges and
the rest from tankships.
These emissions amounted to about 0.2 percent of all volatile
organic emissions nationally. For comparative purposes, this is about
one-tenth the volume of the vapor emissions from automobile refueling.
However, vessel hydrocarbon vapor emissions may be very important
locally. State efforts to meet federal air quality standards have
therefore focused on emissions from marine loading terminals, among
other sources.
Under current air quality regulations, these emissions are generally
not subject to control. Nevertheless, hydrocarbon vapors are important
contributors to ozone generation. Several states are considering con-
trols as a way to meet federal air quality standards for ozone set by
the U.S. Environmental Protection Agency (EPA) under the Clean Air Act.
A number of major metropolitan areas in the United States are not in
attainment of National Ambient Air Quality Standards (NAAQS) for ozone.
THE FEASIBILITY OF VAPOR CONTROL
Technology for controlling these emissions is available and in use;
vessels and marine terminals that load liquefied natural gas, acrylo-
nitrile, and other hazardous fluids routinely capture and reuse or
dispose of loading vapors. It is technically feasible to locate equip-
ment for vapor recovery or disposal either on the vessel or at the
shoreside terminal. Controlling vapors from hydrocarbon loading would
require extending this practice broadly, and undertaking vapor control
at higher loading rates than currently practiced.
Handling potentially explosive vapors could present an added hazard
at barge and tankship terminals. It would also entail substantial
investments and operating costs in the tankship and barge industries.
Loading terminals and vessels would need to install and operate the
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necessary systems. Terminals with low throughputs, inland barges, and
smaller, older tankships would face greater cost impacts than larger
units of the industry.
Equipment needed for vapor control includes systems aboard vessels
that make closed loading possible: devices to protect tanks from over-
pressurization, level monitoring and alarm systems to prevent overfill-
ing, and devices for final cargo gauging and sampling. Closed loading
is done with hatches and ports shut, but it does not necessarily pre-
clude venting of vapors to the atmosphere. Most tankships are equipped
for closed loading, to maintain the required pressure of fire-preventive
inert gas in cargo tanks. Tank barges generally do not use inert gas,
and are usually open loaded.
Terminals would need vapor transport piping, incinerators, or other
equipment for disposal or recovery of vapors, and inert gas generating
and piping systems to prevent the formation of flammable or explosive
vapor-air mixtures in tanks and pipelines. Vessels would need piping
and manifolds to collect vapors and carry them ashore or elsewhere for
disposition. Tank gauging and alarms, detonation arrestors, and other
inline safety devices on vessels and at terminals are needed to prevent
overpressurization and prevent or limit the effects of fires and
explosions.
The complexity of these systems could challenge the engineering,
operational, and personnel training standards of some sectors of the
industry, especially at the lower technology end of the scale, such as
inland barges and small product terminals. Some items of safety equip-
ment, such as detonation arrestors, might require further development
and testing at sizes appropriate to tank barge or tankship loading
rates.
SAFETY AND OPERATIONAL COMPLEXITY
The loading of tank vessels with hydrocarbon cargoes presents three
main hazards: (1) fire due to the ignition of spilled liquid or uncon-
fined vapors, (2) explosion due to the ignition of vapor-air mixtures in
confined spaces, (3) water pollution as a result of spills. An addi-
tional consideration is possible personnel exposure to vapors. The addi-
tion of vapor-handling systems, it has been suggested, could increase
the risks of such events by adding to the operational complexity of
loading operations, and in particular by requiring additional handling
of potentially explosive vapors. Experience to date is too limited to
justify firm conclusions, although it does suggest that proper personnel
training and management can keep the risks of vapor control within the
bounds of normal risks in the industry. Redundant safety systems would
be required at terminals and on board vessels to ensure that the
unnoticed failure of one system would not expose operations to undue
risks.
Certainly, vapor control would require raising operating and train-
ing standards throughout the tank barge and tankship industries to the
levels that obtain in the most technically advanced sectors of those
industries. The operation of vapor control systems would entail stan
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cards of precision and care, for example, well above those considered
normal in the industries. Control of hydrocarbon vapors from vessels
would require raising standards of care and management to levels similar
to those in the most technically sophisticated sectors of the marine
transportation industry. Furthermore, human error is the major cause of
industrial accidents, and management and training programs should
address this fact.
Tank barges generally, and tankships occasionally, are loaded with
hatches and vents open, to allow visual inspection of cargo levels.
Containing vapors will require closed loading, with closed-tank gauging
systems, and will also require vapor collection systems to carry vapors
to disposal or recovery facilities. Experience suggests that the neces-
sary operations could be carried out with little or no increase in
spills or other accidents. The U.S. Coast Guard would have to proceed
on the basis of risk analysis while it and the industries involved
gather the experience necessary to quantify the risks. Such a risk
analysis has not yet been made.
COSTS AND ECONOMIC IMPACTS
The economic impacts of vapor control requirements could be substan-
tial. First, vessel and terminal owners and operators would suffer the
direct costs associated with installing and operating the necessary
systems. The committee's assessment suggests that these costs would
vary widely from vessel to vessel and terminal to terminal. For exam-
ple, estimates indicate that an inland river barge would incur the same
retrofit cost--$168,000--as a 70,000 deadweight-ton crude carrier with
25 times the cargo capacity. Case studies of two actual terminals (see
Chapter 5) show added capital and operating costs that range from more
than $5,000 per ton of emissions abated for a small terminal, loading
1.3 million barrels of gasoline per year, to less than $3,000 per ton of
emissions for a larger terminal, loading 14.9 million barrels per year.
In general, the committee's cost studies show that the cost effective
ness of emission abatement improves with cargo throughput. This could
put small terminals and small inland barge companies at a competitive
disadvantage.
Second, the hydrocarbon vapor control standards under consideration
for marine terminals and vessels would affect the cost-competitiveness
of tank vessels in relation to other forms of transport. Tank vessel
carriage of petroleum cargoes is already declining.
Third, the imposition of standards only in nonattainment areas for
ozone, it has been suggested, would lead many vessel operators to limit
their operations to areas where vapor control is not required, or where
requirements are less stringent. This situation would be exacerbated by
varying and possibly incompatible standards.
Without detailed economic study, it is impossible to gauge the sizes
of these economic impacts. Appropriate regulatory coordination, with
attention to safety and uniformity, can minimize them, but not avoid
them altogether.
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POTENTIAL REGULATORY CONFLICT
Neither the Coast Guard nor the EPA has taken a major initiative to
coordinate or standardize state regulatory development. However, with-
out coordination between these two agencies, state air quality regula-
tory bodies, and industry, a high potential exists for a clash of
regulatory interest between marine safety and air quality goals.
Marine vessels, unlike other mobile emissions sources such as auto-
mobiles, are not expressly regulated by federal air quality legislation.
It is unclear whether EPA may require states to regulate the emissions
of so-called mobile sources (such as vessels) indirectly, by attributing
them to their stationary gathering points (in this case, marine termi-
nals). The agency has taken no positive action on hydrocarbon vapor
emissions from vessels, beyond that involved in reviewing state ozone
compliance plans. Its authority to coordinate state initiatives is
limited.
The Coast Guard, whose responsibility is marine safety, must
ultimately approve the vapor control systems that may be installed on
vessels and at terminals. Uncoordinated development of state regula-
tions could increase risks by fostering a lack of standardization.
Thus, the drive to clean up the air in this case raises the poten-
tial for conflict of national interest between safety and environmental
goals.
The committee found that vapor control is technically feasible with
available technology, that appropriate care by industry and regulators
could satisfy the above concerns, and that uniformity of equipment and
procedures is important. It recommends a coordinated national approach
to developing regulations under the leadership of the Coast Guard, with
the involvement of the EPA, states, and industry. Special attention
should be directed to risk analysis, uniform technical standards, person-
nel training and certification, and investigation of new technologies.
CONCLUSIONS AND RECOMMENDATIONS
1. Of the estimated 56,600 metric tons of hydrocarbon vapor emis-
sions from tank vessels in 1985 (about 0.2 percent of national volatile
organic compound emissions), about 95 percent came from gasoline and
crude oil loaded in tankships and tank barges. Almost all of these
emissions were from vessels in domestic trade. About two-thirds were
from inland tank barges, and the rest were from tankships.
2. Control and recovery of more than 90 percent of hydrocarbon emis-
sions from tankships and tank barges are technically feasible with avail-
able technology. Hydrocarbon vapor emissions may be abated by any of
several technologies to recover or destroy hydrocarbons. Technologies
vary in their efficiency of abatement, with destruction technologies
generally higher in efficiency than recovery technologies.
3. Abatement of hydrocarbon vapor emissions from tank vessels raises
legitimate concerns of safety, cost, economic impact, and operational
reliability. With appropriate government and industry attention, these
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concerns can be addressed. There is as yet too little experience to
project conclusively the safety of planned operations.
RECOMMENDATION: In the absence of historical safety experience,
the U.S. Coast Guard should employ risk analysis in assessing the
safety of the various hydrocarbon vapor emission control alterna-
tives.
4. Safe handling of hydrocarbon vapors will require standardized
equipment and procedures, which include redundant, automated gauging and
alarm devices to prevent overfilling and over or under pressuring, as
well as in-line safety devices such as detonation arrestors.
RECOMMENDATION : Development and testing programs should be
pursued to advance the state of the art in gauging and alarm systems
and also to assure and improve the reliability of large (> 6-in.
diameter) detonation arrestors. The gauges and alarms program
should include addressing the requirements of small, unpowered
vessels, i.e., tank barges.
5. Safe hydrocarbon vapor emission abatement will require trained,
experienced personnel and adequate control of operations by safety-
conscious management. The level of operational control in the tankship
industry is, in general, adequate. However, that in the barge industry
will need to be strengthened.
RECOMMENDATION: The U.S. Coast Guard should revise its per-
sonnel certification requirements for tankermen to ensure that
responsible personnel are fully qualified and trained to maintain
the safety of vapor control operations.
RECOMMENDATION: The tank barge industry should undertake a
voluntary safety consciousness education campaign directed to
operations. This campaign should complement any federal and state
regulatory initiatives.
6. Controlling hydrocarbon vapors from vessels may be cost-effective
in a particular nonattainment area for ozone if tank vessels are a signi
ficant source of hydrocarbon vapor emissions and cargo-loading through
put is sufficient to justify control measures.
7. The economic impact of vapor control regulations will be related
to how the regulations are applied: their timing, the categories of ves
sels or terminals that may be controlled, and the geographical locations
in which the regulations are imposed.
8. If emission controls are to be put in place, a coordinated
national approach is essential to ensure the implementation of uniform
and effective safety practices, with appropriate regard for the effects
on interstate and international commerce. The necessary coordination
could be achieved by amendments to the Federal Clean Air Act, or by a
cooperative interagency program of regulatory development.
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RECOMMENDATION: The U. S . Coast Guard should lead the develop- b
ment and implementation of a coordinated program to ensure the
safety and standardization of maritime hydrocarbon vapor emissions
controls. Such an interagency program should involve, at a minimum
the U.S. Coast Guard and the U.S. Environmental Protection Agency,
operating according to appropriate federal rule-making procedures.
Elements of the program should include:
· vessel safety;
· terminal safety;
· control of emissions; and
· industry safety education.
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9. New vapor control, recovery, and disposal methods may hold
promise as replacements for currently available methods.
RECOMMENDATION: A program of technical research, development,
and testing should be directed to changes in operational procedures
that may reduce emissions, to recovery and disposal technologies
that may offer safer, less costly control measures, and to vapor
barriers and foams that could help reduce hydrocarbon emissions by
controlling vapor generation in cargo tanks.
Representative terms from entire chapter:
hydrocarbon vapor
