Exxon Valdez Oil Spill Disaster Biology Essay

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The purpose of this research is to study on the Exxon Valdez Oil Spill Disaster. This research explains about the basic process and operation of company to bring goods to customer. On the Oil spill disaster, it tries to evaluate all of factors that lead to the oil spill disaster and pollution. It also identifies the consequences of all the hazards of the oil spill disaster on the environment, economy and political. Base on all of above, it looking on the company improvements and changes in the management systems to prevent the disaster from happening.

ExxonMobil is the worlds largest publicly traded integrated petroleum and natural gas company. Company and its affiliates are present on a global scale. They operate facilities and market products around the world, and explore for oil and natural gas on six continents. They lead the industry in almost every aspect of the energy and petrochemical business.

The Exxon Valdez oil spill occurred in Prince William Sound, Alaska, on March 24, 1989, when the Exxon Valdez, an oil tanker bound for Long Beach, California, struck Prince William Sound's Bligh Reef and spilled 260,000 to 750,000 barrels. It is considered to be one of the most devastating human-caused environmental disasters.

Crude oil is the term for unprocessed oil, the stuff that comes out of the ground. It is also known as petroleum. Through a few process and operations, it can be used as fuels, lubricants, and as feedstock in petrochemical processes.

Due to failure to follow the proper procedure in operation, cause the oil spill disaster. Mostly it happen due to human and management issue. We also can see the impact on the environment, economy and political.

The improvements and changes in the management systems so to prevent the disaster from happening have taken. ExxonMobil redoubled its long-time commitment to safeguard the environment, employees and operating communities worldwide.

1. The Aim and Objectives of Exxon Mobil Corporation.

1.1 The Aim of Exxon Mobil

Exxon Mobil Corporation is committed to being the world's premier petroleum and petrochemical company. Until the end, company continuously achieve superior financial and operating results while simultaneously adhering to high ethical standards.

1.2 The Objective of Exxon Mobil

Every day, employees at Exxon Mobil are committed to the pursuit of operational excellence by delivering safe, reliable operations, improving energy efficiency, and maintaining strong business controls. By maximize the value of resources through disciplined investments, developing breakthrough technologies, improving processes, and integrated operations will generates the most benefit for resource owners, society, and our shareholders.

The company have principles guide relationships with shareholders, customers, employees, and communities. With Shareholders, they are committed to enhancing the long-term value of the investment dollars entrusted to company by shareholders. By running the business profitably and responsibly, company expect for shareholders to be rewarded with superior returns. This commitment drives the management of Exxon Mobil Corporation.

With customers, they promise success depends on company ability to consistently satisfy ever changing customer preferences. They commit to be innovative and responsive, while offering high quality products and services at competitive prices.

For their employees, company prepared the exceptional quality of workforce provides a valuable competitive edge. To build on this advantage, company will strive to hire and retain the most qualified people available and to maximize their opportunities for success through training and development. Company are committed to maintaining a safe work environment enriched by diversity and characterized by open communication, trust, and fair treatment.

For communities, company commit to be a good corporate citizen in all the places company operate worldwide. They will maintain high ethical standards, obey all applicable laws, rules, and regulations, and respect local and national cultures. Above all other objectives, they are dedicated to running safe and environmentally responsible operations.

2. The oil and refinery industrial processes and operations.

Crude oil is the term for "unprocessed" oil, the stuff that comes out of the ground. It is also known as petroleum. Crude oil is a fossil fuel, meaning that it was made naturally from decaying plants and animals living in ancient seas millions of years ago and most places crude oil were once sea beds.

Crude oil is a non-uniform material. The composition depends on its location.

The majority of crude oil is alkanes, cycloalkanes (naphthenes), aromatics,

polycyclic aromatics, S-containing compounds, etc.

Gasoline: branched alkanes

Diesel: linear alkanes

Heavier crude contains more polycyclic aromatics

Lead to carboneceous deposits called "coke"

Some crudes contain a lot of sulfur, which leads to processing considerations.

2.1 Refinery Processes

Raw or unprocessed crude oil is not generally useful. Although "light, sweet" (low viscosity, low sulfur) crude oil has been used directly as a burner fuel for steam vessel propulsion, the lighter elements form explosive vapors in the fuel tanks and are therefore hazardous, especially in warships. Instead, the hundreds of different hydrocarbon molecules in crude oil are separated in a refinery into components which can be used as fuels, lubricants, and as feedstock in petrochemical processes that manufacture such products as plastics, detergents, solvents, elastomers and fibers such as nylon and polyesters. Crude oil will go through a few processes before it can use.

2.1.1 Common process units found in refinery


Washes out salt from the crude oil before it enters the atmospheric distillation unit.

Atmospheric distillation

Distills crude oil into fractions.

Vacuum distillation

Further distills residual bottoms after atmospheric distillation.

Naphtha hydrotreater

Uses hydrogen to desulfurize naphtha from atmospheric distillation. Must hydrotreat

the naphtha before sending to a Catalytic Reformer unit.

Catalytic reformer

Used to convert the naphtha-boiling range molecules into higher octane reformate (reformer product). The reformate has higher content of aromatics and cyclic hydrocarbons). An important byproduct of a reformer is hydrogen released during the catalyst reaction. The hydrogen is used either in the hydrotreaters or the hydrocracker.

Distillate hydrotreater

Desulfurizes distillates (such as diesel) after atmospheric distillation.

Fluid catalytic cracker (FCC)

Upgrades heavier fractions into lighter, more valuable products.

Hydrocracker unit

Uses hydrogen to upgrade heavier fractions into lighter, more valuable products.

Visbreaking unit

Upgrades heavy residual oils by thermally cracking them into lighter, more valuable reduced viscosity products.


Treats LPG, kerosene or jet fuel by oxidizing mercaptans to organic disulfides.

Coking (delayed coking, fluid coker, and flexicoker)

Process very heavy residual oils into gasoline and diesel fuel, leaving petroleum coke as a residual product.


Produces high-octane component for gasoline blending.


Converts olefins into higher-octane gasoline blending components. For example, butenes can be dimerized into isooctene which may subsequently be hydrogenated to form isooctane. There are also other uses for dimerization.


Converts linear molecules to higher-octane branched molecules for blending into gasoline or feed to alkylation units.

Steam Reforming

Produces hydrogen for the hydrotreaters or hydrocracker.

Liquified Gas Storage

Store propane and similar gaseous fuels at pressure sufficient to maintain them in liquid form. These are usually spherical vessels or bullets (horizontal vessels with rounded ends.

Storage Tanks

Store crude oil and finished products, usually cylindrical, with some sort of vapor emission control and surrounded by an earthen berm to contain spills.

Slug Catcher

Used when product (crude oil and gas) that comes from a pipeline with two- phase flow, has to be buffered at the entry of the units.

Amine gas treater, Claus unit, and tail gas treatment

Convert hydrogen sulfide from hydrodesulfurization into elemental sulfur.


Such as cooling towers circulate cooling water, boiler plants generates steam, and instrument air systems include pneumatically operated control valves and an electrical substation.

Wastewater collection and treating systems consist of API separators,

Dissolved air flotation (DAF) units and further treatment units such as an activated sludge biotreater to make water suitable for reuse or for disposal.[3]

Solvent Refining

Use solvent such as cresol or furfural to remove unwanted, mainly asphaltenic materials from lubricating oil stock or diesel stock.

Solvent Dewaxing

Remove the heavy waxy constituents petrolatum from vacuum distillation products

2.2 Refinery Operation

Petroleum refining processes and operations can be separated into five basic areas:

Fractionation (distillation) is the separation of crude oil in atmospheric and vacuum distillation towers into groups of hydrocarbon compounds of differing boiling-point ranges called "fractions" or "cuts."

Conversion Processes change the size and/or structure of hydrocarbon molecules. These processes include: :

Decomposition (dividing) by thermal and catalytic cracking;

Unification (combining) through alkylation and polymerization; and

Alteration (rearranging) with isomerization and catalytic reforming.

Treatment Processes to prepare hydrocarbon streams for additional processing and to prepare finished products. Treatment may include removal or separation of aromatics and naphthenes, impurities and undesirable contaminants. Treatment may involve chemical or physical separation e.g. dissolving, absorption, or precipitation using a variety and combination of processes including desalting, drying, hydrodesulfurizing, solvent refining, sweetening, solvent extraction, and solvent dewaxing.

Formulating and Blending is the process of mixing and combining hydrocarbon fractions, additives, and other components to produce finished products with specific performance properties

Other Refining Operations include:

light-ends recovery;

sour-water stripping;

solid waste, process-water and wastewater treatment;

cooling, storage and handling and product movement;

hydrogen production;

acid and tail-gas treatment;

sulfur recovery.

Oil refinery

Flow scheme of a modern refinery

3.0 The Risks Lead To The Oil Spill Disaster and Pollution

Multiple factors have been identified as contributing to the incident. According to M.I.T. course entitled "Software System Safety" by Professor Nancy G. Leveson and the National Transportation Safety Board investigated the accident and determined few probable causes of the incident:

Exxon Shipping Company failed to repair the Raycas radar system, which would have indicated to the third mate an impending collision with the Bligh reef. The management know that the tanker's radar was left broken. Due too expensive to fix and operate, it was disabled for more than a year before the disaster.

Due to fatigue or excessive load, the third mate failed to properly maneuver the vessel.

Exxon Shipping Company failed to supervise the master and provide a rested and sufficient crew for Exxon Valdez.

The oil industry never installed state-of-the-art iceberg monitoring equipment.

Exxon Valdez was sailing outside the normal sea lane to avoid small icebergs thought to be in the area.

The 1989 tanker crew was half the size of the 1977 crew, worked 12−14 hour shifts, plus overtime. The crew was rushing to leave Valdez with a load of oil.

Due to shortage of manpower, Coast Guard tanker inspections in Valdez were not done as schedule.

Tanker crews were not told that the previous practice of the Coast Guard tracking ships out to Bligh reef had ceased.

4.0 The consequences of all the hazards of the oil spill disaster.

When oil is spilled in the ocean, it initially spreads in the water (primarily on the surface), depending on its relative density and composition. The oil slick formed may remain cohesive, or may break up in the case of rough seas. Waves, water currents, and wind force the oil slick to drift over large areas, impacting the open ocean, coastal areas, and marine and terrestrial habitats in the path of the drift.

Oil that contains volatile organic compounds partially evaporates, losing between 20 and 40 percent of its mass and becoming denser and more viscous (i.e., more resistant to flow). A small percentage of oil may dissolve in the water. The oil residue also can disperse almost invisibly in the water or form a thick mousse with the water. Part of the oil waste may sink with suspended particulate matter, and the remainder eventually congeals into sticky tar balls. Over time, oil waste weathers (deteriorates) and disintegrates by means of photolysis (decomposition by sunlight) and biodegradation (decomposition due to microorganisms). The rate of biodegradation depends on the availability of nutrients, oxygen, and microorganisms, as well as temperature.

4.1 Environment Consequences

The effects of the spill continued to be felt for many years afterwards. Overall reductions in population were seen in various ocean animals, including stunted growth in pink salmon populations. The effect on salmon and other prey populations in turn adversely affected killer whales in Prince William Sound and Alaska's Kenai Fjords region. Eleven members (about half) of one resident pod disappeared in the following year. By 2009, scientists estimated the AT1 transient population (considered part of a larger population of 346 transients), numbered only 7 individuals and had not reproduced since the spill; this population is expected to die out. Sea otters and ducks also showed higher death rates in following years, partially because they ingested prey from contaminated soil and from ingestion of oil residues on hair due to grooming. Despite this, there are some things known with a high degree of certainty: oil persisted beyond a decade in surprising amounts and in toxic forms, was sufficiently bioavailable to induce chronic biological exposures, and had long-term impacts at the population level. Three major pathways of long-term impacts emerge:

Chronic persistence of oil, biological exposures, and population impacts to species closely associated with shallow sediments.

Delayed population impacts of sublethal doses compromising health, growth, and reproduction.

Indirect effects of trophic and interaction cascades, all of which transmit impacts well beyond the acute-phase mortality.

Acute Mortality

Marine mammals and seabirds are at great risk from floating oil because they have routine contact with the sea surface. Oiling of fur or feathers causes loss of insulating capacity and can lead to death from hypothermia, smothering, drowning, and ingestion of toxic hydrocabons. Scientists estimate mass mortalities of 1000 to 2800 sea otters, 302 harbor seals, and unprecedented numbers of seabird deaths estimated at 250,000 in the days immediately after the oil spill. Mass mortality also occurred among macroalgae and benthic invertebrates on oiled shores from a combination of chemical toxicity, smothering, and physical displacement from the habitat by pressurized wash-water applied after the spill

Long-term impacts

The persistent nature of oil in sediments produce chronic, long-term exposure risks from some species. For example, chronic exposures for years after the spill to oil persisting in sedimentary refuges were evident from biomarkers in fish, sea otters, and seaducks intimately associated with sediments for egg laying or foraging. These chronic exposures enhanced mortality for years.

Indirect effects can be as important as direct exposure. Cascading indirect effects are delayed in operation because they are mediated through changes in an intermediary. Perhaps the two generally most influential types of indirect interactions are:

trophic cascades in which predators reduce abundance of their prey, which in turn releases the prey's food species from control; and

provision of biogenic habitat by organisms that serve as or create important physical structure in the environment.

Economic Consequences

Recreational Sport Fishing Losses.

This loss was estimated based on the impacts of the spill on sport fishing activity. The fishing activities consider the impact on the number of anglers, the number of sport fishing trips, the areas fished, the species fished for, and the length of these trips.

4.2.2 Tourism Losses.

The spill caused both negative and positive effects. The major negative effects were: Decreased resident and non-resident vacation/pleasure visitor traffic in the spill affected areas due to lack of available visitor services like accommodations, charter boats, air taxis.

Severe labor shortage in the visitor industry throughout the state due to traditional service industry workers seeking high-paying on spill clean-up jobs.

Fifty-nine percent of businesses in the most affected areas reported spill-related cancellations and 16% reported business was less than expected due to the spill.

The principle positive impact was strong business in some areas:

Certain businesses such as hotels, taxis, car rentals and boat charters when the economists coming down to estimate the damage to so-called non-use or existence value of the Prince William Sound region in the wake of the spill.

Replacement costs of birds and mammals. These costs include the relocation, replacement and rehabilitation for some of the shorebirds, seabirds and the marine and terrestrial mammals that may have suffered injury or were destroyed in the Exxon Valdez oil spill.

4.3 Political Consequences

Regulations governing offshore facilities and operations have encouraged the development of improved technology for spill prevention.

A report by the US National Response Team summarized the event and made a number of recommendations, such as changes to the work patterns of Exxon crew in order to address the causes of the accident.

The Oil Pollution Act of 1990 was enacted by the U.S. Congress to strengthen oil spill prevention, planning, response, and restoration efforts. The legislation included a clause that prohibits any vessel that, after March 22, 1989, has caused an oil spill of more than 1 million US gallons (3,800 m3) in any marine area, from operating in Prince William Sound. OPA also set a schedule for the gradual phase in of a double hull design, providing an additional layer between the oil tanks and the ocean. While a double hull would likely not have prevented the Valdez disaster, a Coast Guard study estimated that it would have cut the amount of oil spilled by 60 percent.

As Alaska regulations, in the aftermath of the spill, Alaska governor Steve Cowper issued an executive order requiring two tugboats to escort every loaded tanker from Valdez out through Prince William Sound to Hinchinbrook Entrance. As the plan evolved in the 1990s, one of the two routine tugboats was replaced with a 210-foot (64 m) Escort Response Vehicle (ERV). The majority of tankers at Valdez are no longer single-hulled because Congress has enacted legislation requiring all tankers to be double-hulled by 2015.

Opposition to oil drilling, The Oil, Chemical and Atomic Workers International Union, representing approximately 40,000 US workers, announced opposition to drilling in the Arctic National Wildlife Refuge (ANWR) until Congress enacted a comprehensive national energy policy.

5. The improvements and changes in the management systems to prevent the disaster

The company deeply regretted by a tragic accident, the Exxon Valdez super tanker ran aground in Alaska's Prince William Sound. Company lost than 250000 barrels of oil in just a short period time. The efforts undertaken by stabilize the vessel to prevent father oil spill disaster. Exxon and the U.S. Coast Guard began a massive cleanup effort that eventually involved more than 11,000 Alaskan residents and thousands of Exxon and contractor personnel. In 1992 the U.S. Coast Guard declared the clean up complete.

Company have improvements and changes in the management systems so to prevent the disaster from happen again. In the aftermath of the Exxon Valdez accident, ExxonMobil redoubled its long-time commitment to safeguard the environment, employees and operating communities worldwide. The Exxon Valdez also triggered major improvements in oil spill prevention and response planning.

The U.S. Coast Guard now monitors fully-laden tankers via satellite as they pass through Valdez Narrows, cruise by Bligh Island, and exit Prince William Sound at Hinchinbrook Entrance. The Coast Guard watched the tankers only through Valdez Narrows and Valdez Arm.

Two escort vessels accompany each tanker while passing through the entire Sound. Fifteen years ago, there was only one escort vessel through Valdez Narrows. They not only watch over the tankers, but are capable of assisting them in the event of an emergency, such as a loss of power or loss of rudder control.

Specially trained marine pilots, with considerable experience in Prince William Sound, board tankers from their new pilot station at Bligh Reef and are aboard the ship for 25 miles out of the 70-mile transit through the Sound. Weather criteria for safe navigation are firmly established.

Congress enacted legislation requiring that all tankers in Prince William Sound be double-hulled by the year 2015. It is estimated that if the Exxon Valdez had had a double-hull structure, the amount of the spill would have been reduced by more than half. There are presently three double-hulled and twelve double-bottomed tankers moving oil through Prince William Sound. Two more Endeavor class tankers are under construction by ConocoPhillips, their expected induction into service is 2004 and 2005.

Contingency planning for oil spills in Prince William Sound must now include a scenario for a spill of 12.6 million gallons. Drills are held in the Sound each year.

The combined ability of skimming systems to remove oil from the water is now 10 times greater than it was in 1989, with equipment in place capable of recovering over 300,000 barrels of oil in 72 hours.

Even if oil could have been skimmed up in 1989, there was no place to put the oil-water mix. Today, seven barges are available with a capacity to hold 818,000 barrels of recovered oil.

There are now 40 miles of containment boom in Prince William Sound, seven times the amount available at the time of the Exxon Valdez spill.

Dispersants are now stockpiled for use and systems are in place to apply them from helicopters, airplanes, and boats.