H.J. Styhr Petersen

Marine Transport of Dangerous Goods. Risk Assessment Based on Historical Accident Data

In this paper marine transport of dangerous goods is surveyed on the basis of 151 accident case histories. Accident frequencies have been estimated for the different accident types (collisions, groundings, fire/explosions and structural damage) and are in the range of 1 × 10−3 to 2 × 10−2 per ship per year. Further estimates of the probabilities of spillage of at least 100 tons of cargo and/or fatalities in connection with the accidents have been made. The consequences measured in number of fatalities were compared for each cargo type (oils and chemicals) and it was shown that accidents involving oils were twice as frequent as accidents involving chemicals. However, the distribution of number of fatalities seems to be similar for the two types of goods. Concerning the local surroundings (port, coastal waters and open sea) it was shown that most accidents, both with small and large consequences, happen in coastal waters. The sizes of the spills have been modelled by linear regression based on accident type and the size of the ship. Fairly good correlation between the spill size and the size of the tanker was shown for groundings, structural damage and fire or explosions.

Accidents during marine transport of dangerous goods. Distribution of fatalities

Abstract On the basis of 2781 accident case histories, the consequences measured by the number of fatalities from marine accidents (n = 1780) during transport of dangerous goods have been investigated and compared with those from other transport modes (n = 1001). Accidents from marine transport of dangerous goods have been found to have a larger proportion of accidents with fatalities in the range of 10–50 than other transport modes. Therefore, f N curves for marine accidents are not similar to straight lines as usually seen but have a hump. This is probably due to the size of the potentially affected population, which is often in the range of 10–50 during marine transport, reflecting the number of crew members on one or two vessels; further, the population potentially affected is placed in a limited area. Almost all accidents with more than 40 fatalities were collisions, and accidents with more than 100 fatalities were due to collisions between tankers and ferries, which significantly increases the population at risk. In these accidents, the dangerous goods were oil. The high number of fatalities is not surprising, as oil at sea has the potential for surrounding a vessel and catching fire. Differences have been found for the distribution of fatalities between different local surroundings and transport phases. Similarity has been found for the distribution of fatalities for type of cargo, tank type, geographical location and year of accident.

Marine Accident Frequencies – Review and Recent Empirical Results

Marine accident frequencies reported in 20 different sources have been studied and compared. Further than this, comparisons were made with an analysis done by the present authors. There seems to be consistency within the sources in the use of the terms total loss, casualty and accident/incident. The rates were observed to decrease by an order of magnitude going from accident/incident to casualty and likewise from casualty to total loss. The overall frequencies were found to be in the range of 0·0009 to 0·07 total losses per 10 6 ship miles, 0·03 to 1 casualties per 10 6 ship miles, and 0·5 to 13 accidents/incidents per 10 6 ship miles. It was found that the frequency depends on visibility, brightness, geographical environment, age of vessel and size of vessel. Collision and grounding frequencies were found to increase with decreasing visibility, brightness and more restricted waters. Collision frequencies were found to increase with increasing size of vessel. Fire/explosion and structural damage frequencies were found to increase with increasing age, and collisions to decrease with increasing age. No firm trend was found from the effect of flag state or type of vessel.

A Consequence Model for Chlorine and Ammonia Based on a Fatality Index Approach

Abstract In this paper, a simple and transparent consequence model for chlorine and ammonia is proposed based on a fatality index. The parameters for the model can be estimated from historical accident data and avoid the large number of assumptions necessary in traditional models. This approach was attempted for two values of the exponent of the mass (0.75 and 1.0), from which a simple linear model (with exponent 1.0) is proposed. This estimates consequences for three different population density classes: rural, semi-urban (or industrial) and urban. The distribution of the number of fatalities relative to the estimated average number of fatalities was found to approach an S-shaped distribution function. A simple distribution function gives, however, results comparable to the more complex form. For the particular case of assessing the risk of transportation of chlorine by rail in U.S.A. the fatality index model seems to be less conservative, and closer to empirical observations than the traditional models.

EXPLORING ENVIRONMENTAL EFFECTS OF ACCIDENTS DURING MARINE TRANSPORT OF DANGEROUS GOODS BY USE OF ACCIDENT DESCRIPTIONS

On the basis of 1776 descriptions of water transport accidents involving dangerous goods, environmental problems in connection with releases of this kind are described and discussed. It was found that most detailed descriptions of environmental consequences concerned oil accidents, although most of the consequences were described as reversible changes. It was shown that crude oil releases, on average, are approximately five times larger than releases of oil products and that oil product releases are approximately five times larger than other chemicals. Only 2% of the 1776 accidents described contained information on consequences to living organisms, and only 10% contained any information on consequences to ecosystems. A relationship was found between the minimum kilometers of shore polluted and the tonnes released in the case of shore pollution from oil accidents. Oil slicks were shown to be five times longer than broad. Gravity scales used to describe and evaluate environmental consequences were discussed.

Diffusion of coal gas technology in Denmark, 1850–1920

Abstract A study has been made of the diffusion of coal gas technology in Denmark during the period 1850–1920. There were two seperate periods. In the first, 1850–1868, coal gas was used for lighting only. A number of coal gas works were built. In the 1860s kerosene was introduced and gained a market. No new towns built coal gas works for a time. The introduction of nonsooting premix burners, which made it possible to use coal gas for cooking, and the efficiency improvements of the burners for gas lighting resulted in the building of coal gas works again from about 1885. The building stopped in 1916, although one town built as late as 1927. At the time practically all towns had their own coal gas works, and the supply of electricity was nationwide. Although there is a tendency for larger towns to adopt new technology earlier than the smaller ones, there are many exceptions. In quite a few cases an early adoption of the new technology was due to a single person and his initiative. The diffusion is best described geographically. It first ran along the main traffic routes through Denmark and then out from those. The technology reached the corners of the country rather late. The building of electricity plants later followed the same pattern.

Acceptability of risk — a Danish case

Abstract The only Danish chlorine plant, situated in Copenhagen, has been under study since 1937. In 1987 the Environmental Appeal Board (EAB) dealt with the case. It found that the standard of the plant was second to none. It demonstrated that the societal risk of railway tanker transport of chlorine through Copenhagen was of a similar size as the risk to society of the chlorine stored at the plant. It recommended a general survey of dangerous installations. Finally, it confirmed the decision of the Agency of Environemental Protection (AEP) that the production and storage could continue. An opposition majority in Parliament, however, carried a resolution that a law closing the plant should be proposed. The law was duly proposed, but since then an extraordinary parliamentary election has modified the basis of the coalition Government. The new Minister of Environment will not repropose the law, preferring first to make a general survey of the risks in connection with the chemical industry in Denmark.

Succession of technologies

Abstract The competition between technologies can be very complicated and involve main and by-products and more than one market. This is illustrated with the history of town gas in Denmark. Coal gas failed because coal for house heating was ousted by oil products. New town gas works using oil feedstocks ran into trouble due to competition from power plants in two markets: cooking and house heating by hot water — a by-product of electricity. Larger towns (organizations) are better equipped to defend old technology, but also less flexible to adopt new technology.