Response to Marine Oil Spills: At-sea response

Summary

The video explores global oil consumption and the severe environmental impacts of oil spills. It discusses response strategies, including containment and recovery, dispersants, and in-situ burning. Emphasizing the need for rapid action and well-planned responses, the video showcases techniques and tools used by specialized teams. Real-life examples, such as the Sea Empress and Deepwater Horizon incidents, illustrate the effectiveness and limitations of different methods. The importance of expert planning, ongoing re-evaluation, and understanding the trade-offs in response strategies is highlighted to minimize environmental damage.

Takeaways

• 🌏 Global oil consumption is massive, reaching four billion tonnes annually, highlighting the scale of potential environmental impacts from spills.
• 🚢 Oil spills, though infrequent, can have severe consequences for the environment, livelihoods, and local economies when they occur.
• ❓ The series poses critical questions about the considerations needed for oil spill response, including expertise, techniques, and planning for minimal impact.
• 🛑 Time is of the essence in oil spill response; quick action is key to limiting damage, with a narrow window to act before oil spreads or weathers.
• 🧰 Specialized equipment and trained teams are essential for effective oil spill response, with equipment often pre-packaged and ready for immediate deployment.
• 🚤 Containment and recovery are ideal responses to oil spills, but they are challenging due to oil's rapid spread and changing properties at sea.
• 🔄 Booms and skimmers are primary tools for containing and recovering oil, with booms acting as barriers and skimmers removing oil from the surface with minimal water intake.
• 🌊 The effectiveness of booms and skimmers can be limited by weather conditions, currents, and the need for precise vessel coordination.
• 🔥 In-situ burning is an alternative response method that can remove large oil accumulations under specific conditions, as demonstrated during the Deepwater Horizon incident.
• 🌡️ The use of dispersants can reduce the impact on wildlife and shorelines but requires careful consideration of potential marine environmental effects.
• ♻️ The decision to use dispersants or other response methods involves a Net Environmental Benefit Analysis, weighing the benefits against environmental impacts.

Q & A

How much oil is consumed globally every year?

Globally, we consume four billion tonnes of oil every year.

What are the potential impacts of oil spills on the environment, livelihoods, and local economy?

Oil spills can have severe impacts on the environment, affecting marine life and ecosystems. They can also affect livelihoods by disrupting industries such as fishing and tourism, and can negatively impact the local economy due to cleanup costs and loss of business.

What is the ideal response to an oil spill at sea?

The ideal response to an oil spill at sea is containment and recovery, which involves removing the oil from the marine environment before it reaches the shore.

Why is it challenging to contain and recover oil in water?

Containing and recovering oil in water is challenging because oil spreads out quickly and can cover many square kilometers in just a few hours. Additionally, oil weathers at sea, changing its properties and creating a narrow window of opportunity for response.

What is the importance of having the right equipment and trained teams for oil spill response?

Having the right equipment and trained teams is crucial for an effective oil spill response. The equipment needs to be readily available and properly used, while trained teams ensure that the response is managed effectively and that the right techniques are applied in a timely manner.

What are some of the techniques available for containing and recovering oil spills?

Techniques for containing and recovering oil spills include the use of booms to act as floating barriers, skimmers to recover oil from the sea surface, and mechanical grabs for very viscous weathered oil. Rigid sweeping arms can also be used to guide floating oil towards an integrated pump.

How effective can booms be in containing oil spills under normal weather conditions?

Booms can be very effective in normal weather conditions when there is a thin oil layer, allowing for more oil to be collected into the apex for recovery.

What are dispersants and how do they help in reducing the impact of oil spills on the environment?

Dispersants are chemicals that reduce the amount of wave energy needed to break up an oil slick into small droplets. They are sprayed from vessels or aircraft and help to dilute the oil into the water column, reducing the impact on sea birds, mammals, and sensitive shorelines.

What was the outcome of using dispersants during the Sea Empress oil spill incident in 1996?

During the Sea Empress incident, 445 tonnes of dispersant were used, which successfully removed between 18,000 and 27,000 tonnes of oil from the sea surface and dispersed it into the water column, resulting in a net environmental benefit.

What is in-situ burning and how was it used during the Deepwater Horizon oil spill?

In-situ burning is an alternative response technique that involves igniting oil on the water's surface to remove substantial amounts of oil. During the Deepwater Horizon oil spill, in-situ burning was used in about 400 burns, eliminating around 30,000 to 50,000 tonnes of oil, or about 5% of the total spilled volume.

How is the decision made to stop an oil spill response operation?

The decision to stop an oil spill response operation is based on a technical assessment of whether further efforts are reducing the impact of the oil or mitigating pollution damage. If the response is no longer effective or the environmental trade-offs are not favorable, the operation may be halted.

What is the Net Environmental Benefit Analysis (NEBA) and why is it important in oil spill response?

The Net Environmental Benefit Analysis (NEBA) is a method used to evaluate the environmental trade-offs of different response strategies. It helps in making informed decisions about the use of techniques like dispersants or in-situ burning, ensuring that the chosen response provides the greatest overall benefit to the environment.

Outlines

00:00

🌏 Global Oil Consumption and Spill Response

This paragraph discusses the significant global oil consumption and the environmental, economic, and livelihood impacts of oil spills. It introduces the series' aim to explore key issues, available expertise, and effective response strategies to minimize oil spill impacts. The importance of preparedness and swift action in containment and recovery is emphasized, along with the challenges of oil's rapid spread and changing properties at sea. The paragraph also highlights the necessity for the right tools and skilled teams to manage oil spill responses effectively, exemplified by the European Maritime Safety Agency's oil spill response team in Ferrol, Spain, and their state-of-the-art equipment readiness for rapid deployment.

05:00

🚢 Advanced Techniques in Oil Spill Containment and Recovery

This paragraph delves into the complexities and strategies of containing and recovering oil spills at sea. It explains the use of booms as floating barriers to contain oil near the spill source or deflect it from sensitive areas, and the need for specialized units for offshore deployment. The limitations of booms in fast-moving currents and their resource scarcity are acknowledged, necessitating priority setting in contingency planning. The paragraph also covers various types of skimmers designed for different oil types and conditions, the challenges of operating them, and the use of mechanical grabs for very viscous weathered oil. It further discusses the advantages of rigid sweeping arms for use in rough seas and the importance of storage capacity in oil recovery operations, concluding with the reality that only a small percentage of spilled oil is typically recovered at sea.

10:01

💧 The Effective Use of Dispersants in Oil Spill Response

The paragraph narrates the use of dispersants in oil spill response, focusing on a significant case in Pembrokeshire, South Wales, where the Sea Empress tanker spilled 72,000 tonnes of oil. It describes how 445 tonnes of dispersant were sprayed, primarily from aircraft, targeting the freshest part of the spill. The narrative includes an interview with Dr. Tim Lunel from ITOPF, who shares his firsthand experience and observations of the dispersant's effectiveness in breaking down the oil-in-water emulsion. The summary of the use of dispersants concludes with a discussion on their environmental impact, the trade-offs involved, and the conditions under which their use can provide a net environmental benefit.

15:02

🔥 In-Situ Burning: A Strategic Approach to Oil Spill Management

This paragraph examines in-situ burning as an alternative oil spill response method, illustrated by the Deepwater Horizon incident where around 30,000 to 50,000 tonnes of oil were burned. The explanation includes insights from Dr. Per Johan Brandvik on the process, emphasizing that it is the oil's vapors that burn, necessitating the heating of oil to create these vapors. The discussion covers the methods of ignition, the importance of acting quickly before the oil weathers and becomes less ignitable, and the use of fireproof booms to maintain a thick layer of oil for efficient burning. The paragraph concludes by weighing the increased air pollution from in-situ burning against the potential reduction in marine environmental damage, framing it as a judgment call based on specific spill circumstances.

20:07

🛑 Decision-Making in Oil Spill Response: When to Cease Operations

The final paragraph addresses the critical decision-making process in oil spill response, particularly the decision of when to cease recovery efforts. It discusses the point at which the amount of oil on the water surface becomes minimal, and the efforts to clean it up yield diminishing returns. The importance of recognizing when to stop is highlighted, taking into account the oil type, sea conditions, and the potential environmental impact of continued operations. The paragraph introduces the concept of Net Environmental Benefit Analysis (NEBA) and emphasizes the need for continuous reassessment and adaptation of strategies and techniques throughout the response. It concludes with the idea that a good response may involve a combination of techniques applied at different times and places, and the importance of being prepared and informed to make the best decisions in the event of a spill.

Keywords

💡Oil Spill

An oil spill refers to the release of petroleum hydrocarbons into the environment, often as a result of an accident or operational failure. In the video's context, oil spills are a central theme, highlighting the environmental, economic, and livelihood impacts. The script mentions the rarity of oil spills from shipping accidents and offshore blowouts, but also their severe consequences when they occur.

💡Environmental Impact

The environmental impact encompasses the detrimental effects on ecosystems, wildlife, and natural resources caused by human activities, such as oil spills. The video discusses how oil spills can severely affect marine life and local economies, emphasizing the importance of a well-planned response to minimize these impacts.

💡Response Strategy

A response strategy outlines the actions and measures to be taken in response to an incident, such as an oil spill. The script explores various strategies, including containment and recovery, use of dispersants, and in-situ burning, to address oil spills effectively and minimize environmental damage.

💡Containment and Recovery

Containment and recovery involve the physical capture and removal of oil from the water's surface to prevent it from spreading and causing further harm. The video describes this as an attractive proposition because it removes oil from the marine environment, but notes the challenges due to oil's tendency to spread quickly and change properties at sea.

💡Dispersants

Dispersants are chemicals used to break up oil slicks into smaller droplets, which can then be more easily biodegraded in the water column. The script discusses the use of dispersants to reduce the impact on sea birds, mammals, and shorelines, but also notes the potential environmental trade-offs and the need for careful consideration.

💡In-situ Burning

In-situ burning is a technique where oil is burned at the site of the spill, usually on the water's surface. The video mentions this method as an alternative to containment and recovery and the use of dispersants, highlighting its potential to remove large amounts of oil but also its requirement for specific conditions and the associated air pollution concerns.

💡Booms

Booms are floating barriers used to contain oil near the source of a spill or deflect it away from sensitive areas. The script explains the different types of booms for various conditions and their role in the containment process, emphasizing the need for practice in deploying them effectively.

💡Skimmers

Skimmers are devices that remove oil from the water surface while minimizing water intake. The video describes various types of skimmers suitable for different oil types and conditions, illustrating their importance in the recovery process during an oil spill response.

💡Net Environmental Benefit Analysis (NEBA)

NEBA is a decision-making framework used to evaluate the environmental trade-offs of different response options during an oil spill. The script refers to NEBA when discussing the balance between the environmental benefits and consequences of using dispersants or other response methods.

💡Rigged Sweeping Arms

Rigged sweeping arms are mechanical devices used to guide floating oil towards a pump for recovery. The video highlights their advantage in rough weather conditions and their use during the Prestige spill in 2002, where they contributed significantly to the oil recovery efforts.

💡Storage Barges

Storage barges are floating structures used to store recovered oil or materials during an oil spill response. The script mentions their use to address the challenge of limited storage capacity on smaller vessels, allowing for more effective oil recovery operations.

Highlights

Global oil consumption reaches four billion tonnes annually, emphasizing the scale of potential oil spills.

Oil spills, though rare, have severe environmental, livelihood, and economic impacts.

Key questions about oil spill response strategies are explored in the series.

The importance of a well-planned and executed response to minimize oil spill impact is discussed.

Containment and recovery of oil at sea is highlighted as the ideal response, despite its challenges.

The narrow window of opportunity to act during an oil spill is identified as critical.

Specialist centers prepare equipment for immediate deployment in the event of a spill.

The necessity of skilled teams for effective oil spill response is emphasized.

European Maritime Safety Agency's oil spill response team practices for readiness.

State-of-the-art equipment on commercial vessels includes booms, skimmers, and sweeping arms.

Booms act as floating barriers to contain oil, with deployment strategies discussed.

Skimmers are essential for recovering oil from the sea surface with minimal water intake.

The boom-skimmer combination's effectiveness and operational challenges are analyzed.

Mechanical grabs and rigid sweeping arms are alternative containment and recovery methods.

Storage limitations during oil spill operations and the use of dedicated barges are addressed.

Dispersants can reduce the impact on sea birds, mammals, and shorelines, but have environmental trade-offs.

The effectiveness of dispersants is demonstrated through the Sea Empress incident case study.

In-situ burning as an alternative response method is examined, with its potential and limitations.

The Deepwater Horizon incident is cited as a case where in-situ burning was successfully utilized.

The decision-making process for choosing the right oil spill response strategy is discussed.

Net Environmental Benefit Analysis (NEBA) is introduced as a decision-making tool.

The importance of reassessment and adapting response strategies in real-time is highlighted.

Anticipating possibilities and gathering information for effective oil spill preparedness is emphasized.

Transcripts

Globally we now consume four billion tonnes of oil every year.

Oil spills from shipping accidents and offshore blowouts are rare,

but when they happen, the impact on the environment...

..on livelihoods and on the local economy

can be severe.

In this series, we'll be asking the key questions.

What issues do we need to consider?

What expertise and techniques are available?

How do we deliver a well-planned and executed response to minimise impact?

When there's a spill at sea there's the opportunity

to reduce the amount of oil which reaches the shore,

but to be successful in limiting the damage,

you need to be prepared and act fast.

In this programme we'll look at different strategies

for response at sea,

including the use of dispersants and in-situ burning.

But first let's look at what's often regarded as the ideal response.

Containment and recovery.

Containing and recovering the oil in water is an attractive proposition

because the oil is removed from the marine environment.

But it's challenging.

Oil's natural tendency is to spread out quickly

and it can cover many square kilometres in just a few hours.

Plus, the oil weathers at sea, so its properties change.

This means there's a narrow window of opportunity in which to act.

To contain and recover a spill, a number of techniques are available.

But it's all about getting the right tools for the job

to the right place as quickly as possible.

In the event of an incident, time is critical.

That's why in specialist centres like this one,

the equipment needed following a spill is packaged up and ready to go.

These palettes have already been cleared by customs,

so they can be transported anywhere in the world without delay.

But there's no point having equipment if you don't know how to use it.

We need teams who know what they're doing

led by people with the necessary experience

to manage them effectively.

I've travelled to Ferrol in northern Spain

to catch up with an oil spill response team

from the European Maritime Safety Agency.

These stand-by vessels are in place

to top up pollution response capacities of the EU member states.

They practise regularly, so that when a spill occurs,

they're ready for action.

This commercial vessel is also fitted

with an array of specialist equipment.

Thanks to an arrangement with the owner,

it can be mobilised within 24 hours of an incident.

How well equipped is this vessel?

This vessel has what we call state-of-the-art equipment.

We have booms...

..skimmers

and we have sweeping arms.

In a real spill I would say you don't need 50% of the equipment.

But if you can tell me which equipment I'd need on the next spill,

you'll get a contract with me!

In principle, booms act as floating barriers,

either to contain oil near to the source of the spill

or to deflect it away from sensitive resources.

There's a wide range of booms for different circumstances.

Lightweight, inexpensive booms with solid floatation

can be deployed in harbours,

but offshore we need larger, specialised units

deployed from cranes and reels and then towed

and this takes practice.

When would you use this?

When is the ideal opportunity to deploy the boom?

I would recommend that we use these booms

in normal weather conditions like this.

And if we have a thin oil layer,

then it gives us the opportunity

to collect more, to collect it into the apex.

Then we will deploy

one of these high-capacity skimmers in the centre

and then we can recover it.

Booms need to be towed slowly

and not deployed in areas with fast-moving currents.

More than 0.7 knots at a right angle and they'll begin to fail.

And they're also a limited resource, so not all sites can be protected.

Therefore it's important to set priorities

as part of contingency planning.

Skimmers also come in all shapes and sizes

for dealing with different oil types and conditions inshore and offshore.

Nevertheless, the principle is the same.

They need to recover oil from the sea surface

while minimising water intake.

Weir skimmers often have a floating collar,

which in relatively calm waters enables oil recovery

with as little water as possible.

Oleophilic skimmers are made of material

which attracts oil rather than water.

Oil sticks to the surface and is then scraped or squeezed off

into a sump where it's pumped for storage.

In the right conditions, the boom-skimmer combination

can be very effective, but it does have its limitations.

It is not so easy to operate because you have two vessels

and that makes it difficult

because then you have to move in formation.

Both vessels have to make the same curve at the same time,

taking into account wind, current and all the other issues.

However, it is not going to the moon. Fishermen can do it.

If you practise a little bit... you can manage it.

What's more, even the most sophisticated skimmers

can struggle to pump very viscous weathered oil

and in such situations we may still use mechanical grabs.

Another option for containment and recovery is using rigid sweeping arms

which guide floating oil towards an integrated pump.

The biggest advantage from my point of view

is first it's safe,

you can use it in rough weather conditions

and you need only a minimum crew.

The other thing is you are completely independent with your vessel.

Therefore it is especially used for rough seas

when you have only one vessel

and you don't have to mobilise the other ones.

Therefore it's our primary choice of recovery.

During the Prestige spill in 2002,

equipment like this was used to great effect.

16 specialised response vessels were mobilised,

collecting some 17,000 tonnes of oily waste between them.

Over 70% of this was recovered by just two vessels,

both fitted with rigid sweeping arms.

- Are there disadvantages? - Yes, certainly.

The disadvantage is that it's heavy gear.

You need special equipment, special cranes for it.

You're talking about five tonnes.

One major limiting factor for operations at sea can be storage.

Smaller vessels without much storage can be rapidly overwhelmed

whereas larger vessels like this with plenty of internal capacity

can be difficult to manoeuvre close to shore.

One way to solve the problem is to use dedicated storage barges

or inflatable temporary barges.

But it's important to recognise that for all these efforts

it's rare to recover more than 10% to 15% of spilled oil at sea.

Our next option is a case of weighing the potential benefits

against the possible detrimental impact.

Dispersants, when used appropriately, can help reduce the impact

on sea birds, mammals and sensitive shorelines,

but it's important to be mindful

of how it may affect the marine environment.

Dispersants reduce the amount of wave energy needed

to break the oil slick up into lots of small droplets.

They are sprayed from vessels or aircraft.

The dispersant molecules align at the interface

between the oil and the sea water

and the micron-sized droplets formed as a result

are diluted by the sea's natural mixing energy

and degraded over time by microorganisms.

Dispersants can be sprayed from a variety of different platforms.

It can be a sea-going vessel

or indeed you can spray from the air from a helicopter

or from a fixed-wing plane.

Each have different advantages,

different payloads,

but basically when you're applying dispersant,

you can treat large slick areas in quite a quick time frame,

so spraying dispersant has many advantages.

To get to grips with some of the issues,

I've come to Pembrokeshire in South Wales,

scene of both a serious spill

and also one of the most effective uses of dispersants.

In February 1996, the oil tanker Sea Empress

grounded just over there on the far side of the bay.

She spilled 72,000 tonnes of Forties Blend crude oil into the sea.

A major focus of the response was to spray 445 tonnes of dispersant,

mostly from aircraft.

First focusing on the freshest part of the spill

before moving attention to the larger, more weathered patches.

So was this approach a success?

To answer that I've enlisted the help of Dr Tim Lunel from ITOPF.

Tim, you were here during the Sea Empress incident.

Where were you and what were you doing?

Well, back in February 1996,

a day not very dissimilar to this,

we were out there behind where the DC3 aircraft

were spraying dispersant

onto the freshly released oil coming out of the Sea Empress.

So you were on the water as the aircraft came over.

Was that dicey?

It might sound that way, but we were a well-practised team.

We're used to working together and also the dispersants,

these modern ones are formulated specifically to be very safe.

They're safer than the detergents

you've got as washing-up liquids on your sink.

So that side of it, we didn't have to worry about the dispersants.

We had to think about the toxicity of the oil,

for us and for the marine environment.

From being out there on the water, what did you observe?

When the dispersant was sprayed

on top of the water-in-oil emulsion that was forming,

there wasn't a dramatic effect,

but we could follow that over the following three, four, five minutes.

Look at the wave action working with the oil-dispersant mixture.

We could see the emulsion starting to break down.

After about three or four minutes,

you got that coffee-coloured plume that you look for.

The team continued to apply dispersant for seven days

and carefully observed the effects.

So what did you conclude?

By being out there and using the different monitoring techniques,

we were able to see that the 445 tonnes of dispersant that was used

was able to remove somewhere

between 18,000 and 27,000 tonnes of oil from the sea surface

and disperse it into the water column.

So even if you take the lower figure,

that means that each tonne of dispersant treated 40 tonnes of oil.

This success story is partly down to the type of oil spilled,

Forties Blend being particularly dispersible,

but also the oil spilling over a period of six days

gave the responders a technical advantage.

With these well-practised and targeted teams,

we could really focus on those patches of fresh oil

to make sure the operation was as effective as possible.

And what that meant was that 18,000 to 27,000 tonnes of oil

could have formed a water-in-oil emulsion.

That would have increased its volume by three or four times,

so we could have been looking

at 60,000 to 100,000 tonnes of oil coming ashore.

So it sounds like it was the ideal use of dispersant right here.

It definitely reduced the environmental impact of this spill

because of the circumstances that we had.

It's worth remembering that the oil hasn't disappeared.

It's now in the water column

and we need to think about how it might affect sensitive areas

such as fish-spawning grounds or aquaculture.

The dispersed oil from the Sea Empress

was particularly affecting the shallow populations of bivalves,

clams like cockles

and other shells living in the sediments.

They ejected themselves from the sediment

and were getting washed up on the shoreline in very large numbers.

The effects on other marine life in the waters...

..were largely undetectable.

Most species and habitats around Pembrokeshire

within five years, mostly within two years,

were back to typical normal levels.

But despite this success, it's worth remembering

the use of dispersants is not universally accepted.

In many countries their use is restricted or banned.

When they are used,

even where they reduce the volume of oil reaching the shoreline,

they can generate some negative publicity.

It's important to recognise it's a trade-off.

In the case of the Sea Empress, the use of dispersant resulted

in a Net Environmental Benefit,

but that won't always be the case.

So if, for example, out there we had a coral reef,

taking the oil from the surface and putting it into the water column

wouldn't necessarily provide a Net Environmental Benefit.

We have this hard sand beach

where the oil can be left on the sea surface,

can come ashore and can be removed.

In that case we'd probably not want to disperse it.

If, on the other hand, we were standing in a mangrove,

then the oil would come potentially

into the mangrove area and become trapped

and therefore even though you might still have a coral reef out there,

you might disperse the oil

because you'd reduce the chronic pollution you might get

from oil being trapped within the mangrove

and then being released over time.

That's why it's important in these sensitive environments

to have experts, such as those at ITOPF,

that can really understand the sensitivity to oil pollution

that each individual environment might have

and to understand the response techniques

that can work with those natural processes

to reduce that long-term environmental impact.

Making the decision to use dispersants is rarely easy,

but time is an important factor, so contingency planning is crucial.

And when planning there are a few key things to remember.

First, there is a narrow window of opportunity.

Depending on the oil's properties and the conditions,

that could be a few days or a few hours

because once the oil is weathered, dispersants are less effective.

Second, oil type is crucial.

While light oils readily disperse,

some viscous crudes and heavy fuel oils don't.

And finally the sea state is a factor.

If the sea's calm, the droplets will float to the surface to form a slick,

but if it's too rough and there's lots of wind,

it can be tough to apply the dispersant effectively.

An alternative to containment and recovery and the use of dispersants

which has not been used in many spill incidents

because it requires specific conditions,

but can remove large accumulations of oil

is in-situ burning.

None of us can forget these images, the Deepwater Horizon,

a blowout with severe consequences.

But it's also a case where in-situ burning was widely used.

There were about 400 burns

and they got rid of around 30,000 to 50,000 tonnes of oil.

That's about 5% of the total spilled volume.

Dr Per Johan Brandvik, from the Norwegian research firm SINTEF,

is going to talk me through how it works.

You've carried out a number of controlled field trials with SINTEF

to understand the main parameters for a successful in-situ burn of oil.

What have you found out?

In-situ burning has the potential

to remove substantial amounts of oil

from the sea surface.

But it's important to remember that it's not the oil that burns,

it's the vapours,

so we need to heat the oil to create vapours

for a successful in-situ burning operation.

When it comes to it, how do you light this oil?

How do you ignite it?

You can use a hand-held igniter with a gelled gasoline

or you can use a heli-torch hanging under a helicopter,

dripping burning gelled liquids down on the oil spill.

And when's the window of opportunity?

How quickly do you need to act?

When the oil weathers,

the light components evaporate,

the oil incorporates the water, it emulsifies,

and this makes the ignition of the oil slick complicated,

so we need to act quickly.

In the same way as with dispersants,

there is a time window to act within

and this is different from oil type to oil type.

In the case of the Deepwater Horizon,

the well continued to spill for 12 weeks.

That extended the usual window of opportunity.

What else have you found out from your field trials?

In these field trials we were testing fireproof booms

to prevent the oil from spreading

and to maintain a thick layer

because a thick layer is important for the burning efficiency.

So in this case we had thick layers

and we had an impressive burning efficiency of 80% to 90%.

So you say 80% to 90%. What's left behind?

You end up with a residue, which can be removed mechanically.

Of course, in-situ burning increases air pollution,

the impact of which has to be assessed alongside the alternative,

which is the increased damage to the marine environment.

It's a judgement call

and will depend on the specific circumstance of the spill.

We've looked at containment and recovery,

dispersants and in-situ burning.

But how do we choose the right option for any given spill

and how do we decide when to stop?

I'm meeting with Richard Johnson from ITOPF.

We've seen the options available

and I can imagine in a short space of time,

you're suddenly committing huge resources to a response.

But when do you stop? When do you say, "Enough is enough"?

Inevitably you'll get to a point

when there's only a small amount of oil on the water surface,

through your clean-up endeavours or through natural processes.

And at that point you can be spending a lot of time, effort and resources

chasing bits of oil, but actually achieving very little.

If you've got the glare of the media,

there's nothing better than having aircraft spraying dispersant

or lots of ships with orange boom.

But from our stance, technically,

if you're not reducing the impact of the oil

or mitigating the pollution damage, then you shouldn't be there.

It's important to recognise when to stop

and also to recognise that ultimately it's the oil type,

the sea conditions, the chemistry and the oceanography

that really dictate what can be achieved at sea.

For example, if you've got a small quantity of non-persistent oil,

which is drifting offshore,

then you might need to undertake no action

other to simply monitor and evaluate what's going on.

Similarly, whilst it might seem counterintuitive,

sometimes the best and the easiest option

is to allow oil to come onto certain shore types,

rather than try to mount a full-scale, at-sea response

in adverse weather conditions.

There are times when you can make a difference by being proactive.

Indeed. Absolutely. Don't get me wrong...

You have a spill of persistent oil in calmer conditions

and the ideal choice is to use containment and recovery.

Alternatively, you could be using dispersants

and dispersants are very good at treating a lot of oil very quickly,

particularly if you've got high-energy conditions, high seas

where your containment and recovery isn't going to work.

But there can be an environmental consequence to your actions

and you just have to be fully aware of that

and understand that there's a trade-off.

This is what we very often call

Net Environmental Benefit Analysis or NEBA.

Finally, while we should avoid using strategies

which might directly counteract one another,

selecting a combination of techniques

on different areas of the slick at different times

can provide the optimum solution.

It seems to me that it's not a case of just choosing a type of response

and just blindly sticking to it.

- You constantly revaluate. - You do. Spot-on, yes.

A good response very often needs different techniques,

different strategies at different times

and that reassessment, that revaluation

being continually done is good practice.

So this has been an overview of some of the options available.

To make the best decisions it's important to think ahead,

anticipate the possibilities

and gather as much relevant information as possible.

That way if there is a spill, you can be ready for it.