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Report: Oil tankers pose greatest risk to inlet

Posted: April 26, 2012 - 8:28am  |  Updated: April 26, 2012 - 9:24am

A recent study aimed at determining historical rates and predicting future probabilities of oil spills and other materials into Cook Inlet from marine vessels found tank ships -- those carrying oil as their primary cargo -- have the lowest baseline spill rate.

However, that same report indicates oil tank ships present the greatest risk in Cook Inlet due to their greater oil capacity and concentrated operations in the middle region of the inlet.

The Glosten Associates recently released a draft report titled "Spill Baseline and Accident Causality Study" for use in the Cook Inlet Maritime Risk Assessment project. The Cook Inlet Regional Citizens Advisory Council is one of the lead organizations on project, along with the U.S. Coast Guard and Alaska Department of Environmental Conservation.

According to a press release, the study builds on the findings of a recent Cook Inlet vessel traffic study and estimates, by vessel type, spill frequency and size. It presents a future oil spill rate for 10 years based on 16 years of historical incident data. Glosten Associates, from the vessel traffic study's projected oil movements, also estimated average spill rates. The report also characterizes more than 1,000 spill scenarios developed from seven spill factors and highlights 13 spill scenarios with the highest combined probability and consequence.

"It will help us to help all of the stakeholders in Cook Inlet navigation determine what is the current and projected level of vessel traffic, what is the likelihood of various types of accidents that can occur and it will help us determine how we avoid or eliminate the likely causes of those accidents and mitigate the consequences of the actions should they occur," said Jerry Rombach, CIRCAC Director of Public Outreach.

The results of the report were presented to the Cook Inlet Risk Assessment Advisory Panel and Management team Monday in Anchorage. The report is available for download at The public is also invited to comment on the report's findings through a Friday deadline to

Rombach said several factors make oil tank ships most risky in Cook Inlet.

"The tide and the currents," he said. "This is the second greatest tide in North America and also the currents based not only on tidal flow, but based also on the numbers and volume from streams. ... Third would be the extreme ice conditions that occur throughout the winter months."

He added the presence of numerous oil and gas platforms also present a navigational hazard unique to the area. Projected increases in marine traffic from recent and future oil and gas exploration were also incorporated in the study, Rombach said.

Four types of vessels were looked at in the study including:

* Tank ships carrying crude oil as their main cargo;

* Tank barges, which carry oil but aren't self-propelling and are usually pulled by a tug;

* Non-tank/non-workboat vessels, which do not carry oil as primary cargo, but do include cargo vessels, gas carriers, and passenger vessels;

* Workboats, which include offshore supply vessels, oil spill response vessels, tugs and other vessels with irregular routing and schedules.

In the baseline incident report, numbers of spills and incidents were totaled among those studied vessels. An incident is defined as a mishap that requires attention or response, but may not result in a spill. A spill is not only oil, but can include any number of things that would present a hazard and require response.

The results of the 16 years of study from 1995 to 2010 indicate:

* Tank ships had 12 spills from 24 incidents, 50 percent.

* Tank barges had 24 spills from 31 incidents, 77.4 percent.

* Non-tank/non-workboats had five spills from 27 incidents, 18.5 percent.

* Workboats had 14 spills from 32 incidents, 43.8 percent.

In total, about half of Cook Inlet incidents resulted in a spill during the study period: 114 incidents to 55 spills.

Although tank barges had a higher percent of spills than tank ships or workboats, just looking at the percent does not give the full picture of what's happening, said Eleanor Kirtley, engineer for Glosten Associates.

"The percent spill rate doesn't give how big the spill will be," Kirtley said. "The size of the spill is more a function of the vessel type and the accident type, so that's where a tank ship has the potential for a much larger consequence because it has the potential for a larger spill volume."

In addition, the study found workboats had the highest baseline spill rate at .96 spills per year, the non-tank/non-workboat group had the highest forecasted spill rate at 1.3 spills per year and the total spill rate of the four vessel types is projected at 3.9 per year.

The spill rate was further refined into seven subcategories in the report including vessel types, incidents, vessel movement, oil types, spill sizes, seasons and regions of Cook Inlet.

The regions of Cook Inlet are: lower (Anchor Point south), middle (East Forelands to Anchor Point) and upper (including Knik and Turnagain Arms.) All vessels except oil tank ships had their higher percentage of incidents in the upper region, respectively. Workboats had the highest incident rate in the lower region and non-tank/non-workboats had the highest incident rate in the upper region.

The report details those incident percentages by region as:

* Tank ships -- lower: 17 percent; middle: 58 percent; upper: 25 percent.

* Tank barge -- lower: 13 percent; middle: 42 percent; upper: 45 percent.

* Non-tank/non-workboats -- lower: 26 percent; middle: 26 percent; upper: 48 percent.

* Workboats -- lower: 41 percent; middle: 16 percent; upper: 44 percent.

"The loading docks on both sides of the inlet are in that middle portion," Rombach said. "Most of ... the incidents would involve loading at the ports."

Scenarios were defined for more than 2,000 unique combinations of vessel types and spill factor subcategories, according to the report. A rate and relative consequence was determined for each spill scenario. The majority of those scenarios have a relatively low or very low risk level and a selected set of the highest risk scenarios are detailed in the report, Kirtley said.

The forecasted spill rate for 2015 through 2020 indicates non-tank/non-workboats will have the highest number of spills at 1.29 per year due to an increase in vessel traffic.

Those forecasts included in the report indicate:

* Tank ships -- .0030 spills per vessel traffic day, 242 traffic days per year, with .72 spills per year.

* Tank barge --.0023 spills per vessel traffic day, 408 traffic days per year, with .93 spills per year.

* Non-tank/non-workboats -- .0016 spills per vessel traffic day, 785 traffic days per year, with 1.29 spills per year.

* Workboats -- .0003 spills per vessel traffic day, 3,653 traffic days per year, with .96 spills per year.

Brian Smith can be reached at

Spill survey to generate recommendations

Findings indicating oil tank ships, while having the lowest historical spill rate, present the greatest risk and consequence to Cook Inlet will prompt a regional organization to develop recommendations on it and other high risk scenarios.

The recently released Spill Baseline and Accident Causality Study for use in the Cook Inlet Maritime Risk Assessment project will be used as a guide to help a panel of experts and stakeholders make suggestions on how best to prepare for, mitigate and respond to high-risk and high-consequence marine vessel incidents or spills in the inlet, said Jerry Rombach, Cook Inlet Regional Citizens Advisory Council Director of Public Outreach.

Among the various items detailed in the report were 1,000 spill scenarios ranked by probability and consequence, the bulk of which were deemed low risk. The few that were in the highest risk categories, including a major oil tank spill, will be up for review by the Cook Inlet Risk Assessment Advisory Panel and Management team this September on a priority basis, Rombach said.

“It is going to be a balancing act of incident risk and consequence and it’ll be up to the project manager to lay out those scenarios so that in the course of this workshop appropriate attention is being paid to both the high risk types and the high consequence types,” Rombach said.

That advisory panel met Monday in Anchorage to review the findings of the recently released study, but didn’t get to the business of making recommendations just yet.

“The purpose was not to then go in and say, ‘OK, if the highest risk is tank barges in middle Cook Inlet, what can we do to mitigate those chances of an incident?’” Rombach said.

Such action falls to the project’s next step, which is its ultimate goal — make safe suggestions for the Coast Guard, oil companies, ports and other stakeholders. A combination of state and federal reviews would be needed, Rombach said, to determine which organizations would implement any recommended changes or new rules considering CIRCAC has no enforcement powers.

“The recommendations might be tougher measures in the Coast Guard’s winter ice rules, for example,” Rombach said. “Or they might be recommendations to the ports to have additional service tugs available. Or they might be recommendations to the tanker operators to upgrade their lighting so in nighttime operations they can better see ice conditions on the site.”

— Brian Smith

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spwright 04/26/12 - 02:46 pm
Most Risk ? 4/26/12

None of the Above presents the Most Risk to Our Cook Inlet.

Major Oil Corporations with Attitude present the Greatest Risk for Our Cook Inlet.

British Petroleum & Exxon Mobile & their Proven Attitude towards the Host Nation & Local Residents are the Biggest
Threat to Our Cook Inlet.

B P Killed 11 of It's Own Employees then thru Neglect caused the Greatest Oil Spill in American History & We the State of Alaska continue to Do Business with them ?

AnyOne BUT B P& Exxon They have already PROVEN they can't be Trusted.

SPW "Airborne"

kenai_kid 04/27/12 - 02:11 pm

FYI Exxon Mobile and BP AMOCO have no direct holdings in Cook Inlet. However, a subsidiary of Exxon operates in the inlet (XTO), which to my knowledge has been a good steward to the environment and the industry. BP has no holdings in Cook Inlet that I am aware of. As for "major oil companies" being a threat ... the smaller less financially stable companies would seem to be even less prepared to prevent or respond to a major catastrophic failure or spill and be monetarily ill equipped to rectify and pay for the damages and/or prevent future occurrences. I am fairly certain a Buccaneer or Apache would have a hard time coming up with a $20 billion trust fund to cover future claims and shell out an additional $7+ billion to date as BP has done should they have a spill here and still remain in business.

BP didn't "kill 11 of Its own." It was an occupational accident that killed 11 Trans Ocean employees on a Trans Ocean oil rig leased by BP. While BP is ultimately responsible, it has been the findings of MMS and OSHA that there were many contributing factors outside of BP's direct authority or control that escalated the catastrophe. One such example was Trans Ocean's disabling of the high gas alarm and the fire suppression system on the rig floor for months prior to the blowout.

We continue to do business with companies like BP and Exxon because they own the leases we sold them over the past 50 years in Alaska and realistically, they are best equipped to harvest our resources both financially and technologically. I don't believe arbitrarily nullifying lease agreements would be a good (or legal) business practice in the current economic atmosphere and would more than likely harm the state in future business endeavors.

I am not defending what happened in the gulf, but I understand the risks involved in oil and gas exploration. I also understand accidents happen in all industries. As a result of such accidents, more controls and regulations are put in place. If it weren't for the disasters in Bopal, India and the Phillips Petroleum plant in Texas in the 80's, the PSM standard may not have been a rigorous as it is today and it may not have existed at all.

SPW, I respect your opinion, however, before making conclusions, it is much to our benefit to view the commissions final report and then base our opinions on facts. Otherwise, all we do is spread rhetoric and mis-information that ultimately will hurt us more than it helps us. In other words, we tend to bite off our noses to spite our faces. It is not a perfect world in which we live. We as a people demand more and therefore there will be greater risks taken to meet our demands. If we as a people want less human and environment catastrophes, we will need to curb our demands!
For your review:

spwright 04/27/12 - 03:56 pm
Nice Try 4/27/12

Kenai Kid, Nice Try but nothing that You can say or do will ever change my opinion of British Petroleum & Exxon Mobil.

Just like my visions of the Saudi Royal Family handling Bags of Gold as they board their personal 747 & Laughing All the Way to the Bank.

Once again, IF I were to Agree with You then We would Both Be Wrong.

SPW "Airborne"

kenai_kid 04/28/12 - 04:32 pm
Again SPW

You have me there ... A narrow mind is hard to argue with! If you are going to base your opinion on nothing more than fabricated rhetoric, the results are ... misinformed, illogical and for the most part poor decisions!
Transporting oil has always bore the most risk.
However, NONE of what your first post reflects any reality where the Inlet is concerned. BP isn't here, Exxon's subsidiary is a bit player and, unless you can prove otherwise, Buccaneer has been a good steward and corporate neighbor.

Norseman 04/30/12 - 12:35 pm
no-brainer title

If you asked 1000 residents of this borough what the biggest threat to the inlet is, I am sure 999 would respond to something oil related.
It is inevitable that sooner or later Alaska will suffer another oil related disaster. We all watched the disaster in the gulf last 6 months and they had sunny 70 degree days.
Imagine what it is going to be like when it is 40 below in January and you are up in the Chukchi Sea, or even our inlet.
Alaskans remember only to well exxon treated those affected. It only took over 20 years and they whittled the amount down to a pittance of what the jury had initally awarded.
Lets not forget our Governor was a lawyer for big oil back then and a former oil lobbyist to boot.
We need to raise the taxes on big oil, not lower them.

Watchman on the Wall
Watchman on the Wall 04/30/12 - 07:44 pm
Man is Greatest threat to Cook Inlet

The Greatest threat to Cook inlet if there is an oil spill is all the manmade chemicals that are used to try & disperse the oil. God has created micro organisms that eat natural oil and will clean up the oil if left alone to do so. In the North Atlantic where a field of volcanic vents called Lost City are creating & pumping out massive amounts of oil into the ocean every single day due to the right chemical and heat balance needed to do this natural action.
The Germans had two scientists that used this action of just the right amount of heat applied to coal to produce oil, then gas during WWI for their war machines. This is called the FTT process or Fisher-Tropsch Type and is exactly what happens in the earth each second to replenish billions of gallons of oil that is used world wide.

Mankind is the Greatest threat to Cook Inlet or the Gulf of mexico or any where else if there is an oil spill due to all the manmade junk that is used to try & clean up the mess which nature will do if left alone.
Will there be a short time of polluted beaches or dead marine animals? Yes, but not as bad if left alone & natures course is thrown off by mans created chemicals that do more harm than good.

God has a Plan for everything, man has another Plan for everything which is always more distructive for everything & everyone when applied. Man always wants his way instead of accepting Gods way and that applies to everything.
Gods eternal plans will all come to pass inspite of mans grand plans of recreation and taking credit for all kinds of supposed good ideas which are never lasting or much good compared to what God created and said was Good.

Jeremiah 6:17

kenai_kid 05/01/12 - 07:45 am

First, the the Fischer Tropshe Type of fuel requires a catalyst to make the conversion to synthetic diesel fuel and can be done with wood, coal or natural gas. In any case, it takes energy to force the reaction if it is to be induced by man made means. Second, the "Lost City" vents you write of are in fact not oil, but methane and hydrogen. There are oil seeps around the world and several here in Alaska, but none that I know of are in the range of even a hundred of barrels per day. None of the seeps I have been able to find references for are under any significant pressure and most (all) are ... seeps where oil simply oozes from a fracture to the surface where it pools.
I am not arguing that oil is not renewable. I don't agree with the theory, but that does not mean it isn't so. However, we have truly renewable resources (food) in which our demand out paces the renewal process. In other words, even if oil IS renewable, we may be using it far faster than it can replenish itself.
Please, if you have a link that supports your theory, feel free to post it.
Finally, I do agree with a portion of your post ... Man is the biggest threat to Cook Inlet.

Watchman on the Wall
Watchman on the Wall 05/01/12 - 10:19 am
KK Very good & Thanks

KK Very good & Thanks
I figured you would help inlighten me further on this process which i only know a small amount about from an article i read in Prophecy In The News .com magizine dated March 2008 titled "And God Created Oil."
Speaking of renewable foods what about everything now being genetically altered and the distruction of all natural foods, seeds by these genetic alterations, is this whats causing mankinds many illnesses? I think it is and what a money maker for many due to all these altered foods & illnesses related to them.
At every turn mankind is trying to recreate everything that God created and said was Good. Mankind only messes up in the process i do believe and causes more harm to humans as well as all life forms on earth and does these things as a means for OUR desire to control OUR own destiny promoting the religion of man over Gods choosen plan.
One day God will say ENOUGH, then it's judgement time for all that have rejected his plans for their own.
The movie with Jennifer Lopez called Enough is a prime example of what Gods gonna do some day to all that abuse him & his plans. Sad that it has to get to that point in the movie and life in general, but it does and will.

Have a GR8 MayDay and thanks for the info.

Jeremiah 6:17

ziggyak 05/05/12 - 01:04 pm
Over the years I have seen

In the past 55 years I have seen rig (platform) blowouts, seepage from Chevron refinery, and many ships (all sizes) sinking in the inlet. The platforms are an ever present danger of a release but in the long term we have an aging commercial fishing fleet (not all well maintained) and on the river and in the inlet the commercial charter operators, pumping bilges and a few sink every year. It seams to me the combined commercial/sport fishing will end up putting more into the water than the oil industry. If oil industry has another big spill it will be from failure to infrastructure (pipelines under Cook Inlet). But as I mentioned above the spills I have seen in the past have cleaned them selves up with the volume of water moving through Cook Inlet and aggressive wave action of our storms. The large spills of the past had little impact that I can remember on the commercial fishing.

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