Oil bergs may be used as temporary containment to reduce the spreading effect of oil, as a way to collect and move the oil into containment or may be used as a way to improve in-situ burning efficiency when salvage is not deemed possible because of weather or logistics.

One pound of dry ice pellets will freeze three pounds of crude or fuel oil. While the freezing process is fairly independent of sunlight, air, seawater and initial oil temperature, the length of time the oil stays frozen depends on the thickness of the oil, the temperature of the water and air, wind velocity and sunlight intensity.

Once the oil is frozen, it may be folded back on itself mechanically to from a frozen oil/dry ice pellet "sandwich" structure perimeter working from small boats. Alternatively, a frozen patch can be collapsed back on itself to form a blob by pouring more dry ice pellets on the center of the frozen patch until it sinks. The thicker the frozen oil formations, the longer it persists. It is often most useful to freeze small amounts of oil just before it is picked up off the water to be placed inside a container.

The icy waters with some ice are optimum for prolonged freeze containment per a single application of dry ice pellets. It is in these conditions that most of the other means of oil spill remediation (i.e. booms, bacteria, dispersants, adsorbing onto plastic or paper) work least effectively.

The very small dry ice pellets used to freeze the oil should be applied as to cover the oil from 8 to 30 ounces per square foot depending on oil thickness with thicker oil needing more dry ice pellets to freeze it solid. Regardless of oil thickness, you will get oil freezing on a top layer as each individual pellet freezes the oil around itself over the course of its sublimation.

Small dry ice pellet sizes up to 3/16inch (.1875 inch) diameter float on oil and water are used in the initial oil freezing procedure. Recovery of oil from very thick oil layers requires the dry ice pellets freeze the oil solid and be removed by several attempts for full recovery. Alternatively if the oil is not moving, thick oil (an inch thick to three inches) can be frozen solid by these small pellets over three to five hours.

A large reduction in freezing time of very thick oil layers can be had by using larger than ¼ inch diameter dry ice pellets once a thin frozen skin is achieved as to support these larger normally sinking dry ice pellets (½ inch diameter) which deform the surface of the oil and penetrate the oil layer so the oil is frozen from the inside dry ice pellets and not just from the top surface down. This is an art because this short cut method depends on large dry ice pellets not sinking below the oil layer and into the water below and releasing a gush of oil dispersing bubbles when the oil is not in a boom or nearly solid.

Dry ice pellets and chunks over about 3/16-inch diameter size will sink and sublimate a stream of carbon dioxide bubbles. The bubbles can be used to induce surface currents that can be used to herd the spilled oil. These oil-herding techniques can be used when the oil is on fire or to be collected is in shallow (to 50 feet) water. The larger the pellet or block of dry ice, the longer the dry ice will sublimate a stream of bubbles used in the oil spill herding technique.

When a patch of spilled oil is surrounded by large dry ice pellets and blocks, the oil is collected into a spinning contiguous mass on the surface by surface currents induced by the Coriolis effect as the bubble streams rise. Throw in a net or rope. Freeze the slowing spinning oil by and collect the frozen oil.

This cryogenic technology bridges the need to use dispersants and bacterial remediation in all but the final stages of a lead agency clean up protocol. Both bacterial and dispersant effectiveness should both be expected to decrease in colder Artic waters where drilling is anticipated. This cryogenic technology efficiency is enhanced by cold water; however, because oil is a thermal insulator this method has been shown to work well on warm (85 degrees F.) water conducted for a major oil company.

The cryogenic process of oil spill containment is a quantum advancement in oil spill remediation over current collection onto paper or plastic, in that the oil is preserved by the low temperature and recovered in a less degraded condition as a pure substance solid. This may mean that the oil can be recovered for use or recycle, rather than for burning or landfill deposit.

There is also a public safety gap that will be bridged better when cryogenic methods are employed in that toxic fumes (VOC emissions) are reduced significantly from the crude or fuel oils during the clean up process. As the reader may know, four Japanese clean up workers died from fuel oil fumes during the clean up of a Russian tanker in 1997. There are highly toxic crude oils from republics formed from the break-up of the U.S.S.R. when spilled are highly problematic to clean up, except perhaps by freeze recovery.

This spinning mass may be frozen solid and then collected up off the water straight away to reduce odor and increase the efficiency of collection. A shovel with holes in it to let the water out without letting the frozen oil escape helps to collect small frozen amounts of oil. Throwing a rope or net that floats in with the oil before it is frozen, as mentioned, helps collect oil bergs by later just pulling in the net or rope and collecting the oil attached.

The spillage rate may be reduced or contained at the source by a crude or fuel oil patch in the tanker itself. The spillage may be contained in proximity to the stricken vessel, but removed a bit as to not impact vessel salvage work. Just before grounding the oil may be captured just beyond the surf line in shallow water by "oil spill herding techniques" mentioned above. Finally, the grounding oil may be frozen and rolled up like an old carpet off wet sand on the beach before it soaks into the sand avoiding toxic fumes and air pollution for down wind populations.

One more point about the frozen oil-it eventually melts allowing the collected oil to be handled by current oil moving technology, i.e. pumps and hoses. This is a great advantage over the use of permanent solidifying chemicals that can cause current recovery machines to become clogged.

The point is not to freeze an acre or square mile of very thin and patchy oil only to let it melt back into liquid on the water surface. Responder vessels pulling booms would seem to work best followed by aerial spraying of dispersants and bacteria over the oily residue when the spilled oil has had many days to reach thermodynamic equilibrium with currents, wind, gravity, surface tension, entropy and oxidation.

The delivery of cryogenic ordnance (packages of dry ice pellets suitable for air dispersal), guns shooting dry ice pellets and free dry ice hail shoveled, poured or dropped onto the leading edges of a river of oil spreading with the current and wind from a stricken vessel or drilling platform will cause the oil and seawater (when sea temperatures are 62 degrees Fahrenheit or lower) to freeze and become an impediment to the rate of oil spill spread.

In some instances, especially when the spilled oil is far from shore and when recovery barges are days away, the decision might be to tow the oil bergs away from the stricken vessel and set them on fire. Once a fire is started on a portion of melted oil, the oil will burn and the radiant heat will melt more frozen oil in the fire's path and so the fire will burn up the melted oil while still being contained by a ring of still frozen oil. In this way it is thought that freeze containment will act to improve in-situ burning efficiency.

When close to shore or in a harbor the spilled oil may be quickly herded and collected by first throwing a net in with the oil, before it is frozen. After freezing, the oil bergs then may be picked up off the water by helicopter or vessel. Small oil bergs when frozen and picked up off the water by imbedded net do not leak or drip oil and may be moved by helicopter or responder vessel some distance into a boomed area or permanent storage containers to let melt back into fuel or crude oil suitable for transfer for use or recycle by pumping.

Need immediate assistance? Help with an oil spill contact HtH Oil Spill Project Manager by e-mail at timbecktoo@hotmail.com or by phone.

Attention: Marine fueling station operators! Contact Heal the Harbor and we will help set up a delivery schedule from a dry ice supplier. Stock several 5 pound plastic bags (@ $5.00 each retail) of 1/8 inch diameter and ½ inch diameter sizes dry ice pellets with a few pounds of loose ½ inch pellets on top (so the semisealed 5 lb. bags won’t loose weight; therefore, we call these loose dry ice pellets on the bottom and top of storage, “sacrificial pellets” and may be provided by the dry ice supplier free)in an ice chest (of a type that you have for sale)near the cash register.

Put up a sign so people know you now have dry ice and that customers can order larger amounts for longer voyages. Sell safety gloves and goggles. Have customers sign for the ice, to follow safety instructions and remind them not to freeze their beer by putting it in with dry ice.

For a dry ice supplier, look on-line or in the phone book for the nearest supplier. All things being equal, we recommend Airgas Inc. because of their donations of dry ice used for this and other (ski resort snow conditioning without ammonium nitrate and insect disinfestations without poison) environmental projects.

If an Airgas supplier is not local and the purchase is big, then Airgas Santa Fe Springs, CA. (dry ice division) is also experienced at shipping many tons of tiny dry ice pellets by air transport to almost anywhere in the world.

Still having trouble finding a small, local supplier of dry ice "rice" for environmental work at a reasonable price? WE'll TRY TO HELP!

Send a SASE to:

Heal the Harbor OSPR (oil spill project research)
P.O. Box 3182
M.B., CA 90266

We will send back the name and address of a dry ice supplier near you and we will also see if we can get you an environmental discount.

*Notices on Safety for dry ice
* Keep out of the reach of children.
* Do not handle with bare hands.
* Do not confine in stoppered bottles or other tightly closed containers.
* Do not enter poorly ventilated spaces where dry ice is used or stored in large quantities.
* Extremely Cold (-109 degrees F)

In addition: Tiny dry ice pellets may accumulate a static electric charge during production, transportation and storage and should be discharged to ground to avoid being startled or around flammable gas.

If you are a teacher, student or first responder and want to try and demonstrate dry ice oil spill recovery techniques for a class, project or testing as outlined above, then we strongly recommend that you replace toxic, carcinogenic crude or fuel oil with olive oil. Olive oil freezes and acts like fuel oil, but without the bad odor, health and safety problems, skin irritation and other clean up problems of real crude or fuel oil.

Anyone wishing to invest in and share patent rights within one year of the publication of the above method of oil spill remediation should contact Heal the Harbor by a letter.