ABSTRACT
A group of more than 25 agencies from Canada and the United States conducted a major offshore burn near Newfoundland, Canada, in 1993. Two batches of oil, about 50 tons each, were released into a fireproof boom. Each burn lasted more than one hour and was monitored for emissions and physical parameters. Over 200 sensors or samplers were employed to yield data on over 2000 parameters or substances. The experiment was the largest of its type ever conducted. The operation was extensive, with over 20 vessels, 7 aircraft and 230 people involved in the at-sea operation. The experiment resulted in extensive analytical data as well as significant operational data, some of which are presented in this chapter.
The quantitative analytical data show that the emissions from this in-situ oil fire were less than expected. All compounds and parameters measured were below health concern levels beyond about 150 m from the fire, very little being detected beyond 500 m. The fate and behaviour of oil components in fires are, in many cases, the subject of further research. Pollutants were found to be at lower values in the Newfoundland offshore burn than they were in prior pan tests. The reason for this is the larger scale of the burn, resulting in more efficient combustion.
Polyaromatic hydrocarbons (PAHs) were found to be lower in the soot than in the starting oil and were consumed by the fire to a large degree. Particulates in the air were measured by several means and found to be of concern only up to 150 m downwind at sea level. Particulate matter may not be a concern past this distance except perhaps in the plume remnants. Combustion gases including carbon dioxide, sulphur dioxide and carbon monoxide did not reach levels of concern. These gases were emitted over a broad area around the fire and were not directly associated with the plume trajectory. Volatile organic compounds (VOCs) were abundant; however, they were less than emitted from the non-burning spill. Over 50 compounds were quantified, most at levels that would not cause concern.
Water under the burns was analysed; no compounds of concern could be found at the detection level of the methods employed. Toxicity tests performed on this water did not show any adverse effect. The burn residue was analysed for the same compounds as the air samples. PAHs were found at lower concentrations in the residue than in the starting oil. The overall mass of PAHs, including that of the higher-molecular-weight species, was about 6 orders of magnitude lower after the burn. Overall, indications from these burn trials are that emissions from in-situ burning are low in comparison to other sources of emissions and result in acceptable concentrations of air contaminants.
