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Friday, 25 February 2011 17:08

Transportation of Hazardous Material: Chemical and Radioactive

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The industries and economies of nations depend, in part, on the large numbers of hazardous materials transported from the supplier to the user and, ultimately, to the waste disposer. Hazardous materials are transported by road, rail, water, air and pipeline. The vast majority reach their destination safely and without incident. The size and scope of the problem is illustrated by the petroleum industry. In the United Kingdom it distributes around 100 million tons of product every year by pipeline, rail, road and water. Approximately 10% of those employed by the UK chemical industry are involved in distribution (i.e., transport and warehousing).

A hazardous material can be defined as “a substance or material determined to be capable of posing an unreasonable risk to health, safety or property when transported”. “Unreasonable risk” covers a broad spectrum of health, fire and environmental considerations. These substances include explosives, flammable gases, toxic gases, highly flammable liquids, flammable liquids, flammable solids, substances which become dangerous when wet, oxidizing substances and toxic liquids.

The risks arise directly from a release, ignition, and so on, of the dangerous substance(s) being transported. Road and rail threats are those which could give rise to major accidents “which could affect both employees and members of the public”. These dangers can occur when materials are being loaded or unloaded or are en route. The population at risk is people living near the road or railway and the people in other road vehicles or trains who might become involved in a major accident. Areas of risk include temporary stopover points such as railway marshalling yards and lorry parking areas at motorway service points. Marine risks are those linked to ships entering or leaving ports and loading or discharging cargoes there; risks also arise from coastal and straits traffic and inland waterways.

The range of incidents which can occur in association with transport both while in transit and at fixed installations include chemical overheating, spillage, leakage, escape of vapour or gas, fire and explosion. Two of the principal events causing incidents are collision and fire. For road tankers other causes of release may be leaks from valves and from overfilling. Generally, for both road and rail vehicles, non-crash fires are much more frequent than crash fires. These transport-associated incidents can occur in rural, urban industrial and urban residential areas, and can involve both attended and unattended vehicles or trains. Only in the minority of cases is an accident the primary cause of the incident.

Emergency personnel should be aware of the possibility of human exposure and contamination by a hazardous substance in accidents involving railways and rail yards, roads and freight terminals, vessels (both ocean and inland based) and associated waterfront warehouses. Pipelines (both long distance and local utility distribution systems) can be a hazard if damage or leakage occurs, either in isolation or in association with other incidents. Transportation incidents are often more dangerous than those at fixed facilities. The materials involved may be unknown, warning signs may be obscured by rollover, smoke or debris, and knowledgeable operatives may be absent or casualties of the event. The number of people exposed depends on population density, both by day and night, on the proportions indoors and outdoors, and on the proportion who may be considered particularly vulnerable. In addition to the population who are normally in the area, personnel of the emergency services who attend the accident are also at risk. It is not uncommon in an incident involving transport of hazardous materials that a significant proportion of the casualties include such personnel.

In the 20-year period 1971 through 1990, about 15 people were killed on the roads of the United Kingdom because of dangerous chemicals, compared with the annual average of 5,000 persons every year in motor accidents. However, small quantities of dangerous goods can cause significant damage. International examples include:

  • A plane crashed near Boston, USA, because of leaking nitric acid.
  • Over 200 people were killed when a road tanker of propylene exploded over a campsite in Spain.
  • In a rail accident involving 22 rail cars of chemicals in Mississauga, Canada, a tanker containing 90 tonnes of chlorine was ruptured and there was an explosion and a large fire. There were no fatalities, but 250,000 persons were evacuated.
  • A rail collision alongside the motorway in Eccles, United Kingdom, resulted in three deaths and 68 injuries from the collision, but none from the resulting serious fire of the petroleum products being transported.
  • A petrol tanker went out of control in Herrborn, Germany, burning down a large part of the town.
  • In Peterborough, United Kingdom, a vehicle carrying explosives killed one person and almost destroyed an industrial centre.
  • A petrol tanker exploded in Bangkok, Thailand, killing a large number of people.

 

The largest number of serious incidents have arisen with flammable gas or liquids (partially related to the volumes moved), with some incidents from toxic gases and toxic fumes (including products of combustion).

Studies in the UK have shown the following for road transport:

  • frequency of accident while conveying hazardous materials: 0.12 x 10–6/km
  • frequency of release while conveying hazardous materials: 0.027 x 10–6/km
  • probability of a release given a traffic accident: 3.3%.

 

These events are not synonymous with hazardous material incidents involving vehicles, and may constitute only a small proportion of the latter. There is also the individuality of accidents involving the road transport of hazardous materials.

International agreements covering the transport of potentially hazardous materials include:

Regulations for the Safe Transport of Radioactive Material 1985 (as amended 1990): International Atomic Energy Agency, Vienna, 1990 (STI/PUB/866). Their purpose is to establish standards of safety which provide an acceptable level of control of the radiation hazards to persons, property and the environment that are associated with the transport of radioactive material.

The International Convention for the Safety of Life at Sea 1974 (SOLAS 74). This sets basic safety standards for all passenger and cargo ships, including ships carrying hazardous bulk cargoes.

The International Convention for the Prevention of Pollution from Ships 1973, as modified by the Protocol of 1978 (MARPOL 73/78). This provides regulations for the prevention of pollution by oil, noxious liquid substances in bulk, pollutants in packaged form or in freight containers, portable tanks or road and rail wagons, sewage and garbage. Regulation requirements are amplified in the International Maritime Dangerous Goods Code.

There is a substantial body of international regulation of the transportation of harmful substances by air, rail, road and sea (converted into national legislation in many countries). Most are based on standards sponsored by the United Nations, and cover the principles of identification, labelling, prevention and mitigation. The United Nations Committee of Experts on the Transport of Dangerous Goods has produced Recommendations on the Transport of Dangerous Goods. They are addressed to governments and international organizations concerned with the regulation of the transport of dangerous goods. Among other aspects, the recommendations cover principles of classification and definitions of classes, listing of the content of dangerous goods, general packing requirements, testing procedures, making, labelling or placarding, and transport documents. These recommendations—the “Orange Book”—do not have the force of law, but form the basis of all the international regulations. These regulations are generated by various organizations:

  • the International Civil Aviation Organization: Technical Instructions for Safe Transport of Dangerous Goods by Air (Tis)
  • the International Maritime Organization: International Maritime Dangerous Goods Code (IMDG Code)
  • the European Economic Community: The European Agreement Concerning the International Carriage of Dangerous Goods by Road (ADR)
  • the Office of International Rail Transport: Regulations Concerning the International Carriage of Dangerous Goods by Rail (RID).

 

The preparation of major emergency plans to deal with and mitigate the effects of a major accident involving dangerous substances is as much needed in the transportation field as for fixed installations. The planning task is made more difficult in that the location of an incident will not be known in advance, thus requiring flexible planning. The substances involved in a transport accident cannot be foreseen. Because of the nature of the incident a number of products may be mixed together at the scene, causing considerable problems to the emergency services. The incident may occur in an area which is highly urbanized, remote and rural, heavily industrialized, or commercialized. An added factor is the transient population who may be unknowingly involved in an event because the accident has caused a backlog of vehicles either on the public highway or where passenger trains are stopped in response to a rail incident.

There is therefore a necessity for the development of local and national plans to respond to such events. These must be simple, flexible and easily understood. As major transport accidents can occur in a multiplicity of locations the plan must be appropriate to all potential scenes. For the plan to work effectively at all times, and in both remote rural and heavily populated urban locales, all organizations contributing to the response must have the ability to maintain flexibility while conforming to the basic principles of the overall strategy.

The initial responders should obtain as much information as possible to try to identify the hazard involved. Whether the incident is a spillage, a fire, a toxic release, or a combination of these will determine responses. The national and international marking systems used to identify vehicles transporting hazardous substances and carrying hazardous packaged goods should be known to the emergency services, who should have access to one of the several national and international databases which can help to identify the hazard and the problems associated with it.

Rapid control of the incident is vital. The chain of command must be identified clearly. This may change during the course of the event from the emergency services through the police to the civil government of the affected area. The plan must be able to recognize the effect on the population, both those working in or resident in the potentially affected area and those who may be transients. Sources of expertise on public health matters should be mobilized to advise on both the immediate management of the incident and on the potential for longer-term direct health effects and indirect ones through the food chain. Contact points for obtaining advice on environmental pollution to water courses and so on, and the effect of weather conditions on the movement of gas clouds must be identified. Plans must identify the possibility of evacuation as one of the response measures.

However, the proposals must be flexible, as there may be a range of costs and benefits, both in incident management and in public health terms, which will have to be considered. The arrangements must outline clearly the policy with respect to keeping the media fully informed and the action being taken to mitigate the effects. The information must be accurate and timely, with the spokesperson being knowledgeable as to the overall response and having access to experts to respond to specialized queries. Poor media relations can disrupt the management of the event and lead to unfavourable and sometimes unjustified comments on the overall handling of the episode. Any plan must include adequate mock disaster drills. These enable the responders to and managers of an incident to learn each other’s personal and organizational strengths and weaknesses. Both table-top and physical exercises are required.

Although the literature dealing with chemical spills is extensive, only a minor part describes the ecological consequences. Most concern case studies. The descriptions of actual spills have focused on human health and safety problems, with ecological consequences described only in general terms. The chemicals enter the environment predominantly through the liquid phase. In only a few cases did accidents having ecological consequences also affect humans immediately, and the effects on the environment were not caused by identical chemicals or by identical release routes.

Controls to prevent risk to human health and life from the transport of hazardous materials include quantities carried, direction and control of means of transport, routing, as well as authority over interchange and concentration points and developments near such areas. Further research is required into risk criteria, quantification of risk, and risk equivalence. The United Kingdom Health and Safety Executive has developed a Major Incident Data Service (MHIDAS) as a database of major chemical incidents worldwide. It currently holds information on over 6,000 incidents.


Case Study: Transport of Hazardous Materials

An articulated road tanker carrying about 22,000 litres of toluene was travelling on a main arterial road which runs through Cleveland, UK. A car pulled into the path of the vehicle, and, as the truckdriver took evasive action, the tanker overturned. The manlids of all five compartments sprang open and toluene spilled on the roadway and ignited, resulting in a pool fire. Five cars travelling on the opposite carriageway were involved in the fire but all occupants escaped.

The fire brigade arrived within five minutes of being called. Burning liquid had entered the drains, and drain fires were evident approximately 400m from the main incident. The County Emergency Plan was put into action, with social services and public transport put on alert in case evacuation was needed. Initial action by the fire brigade concentrated on extinguishing car fires and searching for occupants. The next task was identifying an adequate water supply. A member of the chemical company’s safety team arrived to coordinate with the police and fire commanders. Also in attendance were staff from the ambulance service and the environmental health and water boards. Following consultation it was decided to permit the leaking toluene to burn rather than extinguish the fire and have the chemical emitting vapours. Police put out warnings over a four-hour period utilizing national and local radio, advising people to stay indoors and close their windows. The road was closed for eight hours. When the toluene fell below the level of the manlids, the fire was extinguished and the remaining toluene removed from the tanker. The incident was concluded approximately 13 hours after the accident.

Potential harm to humans existed from thermal radiation; to the environment, from air, soil and water pollution; and to the economy, from traffic disruption. The company plan which existed for such a transportation incident was activated within 15 minutes, with five persons in attendance. A county offsite plan existed and was instigated with a control centre coming into being involving police and the fire brigade. Concentration measurement but not dispersion prediction was performed. The fire brigade response involved over 50 persons and ten appliances, whose major actions were fire-fighting, washing down and spillage retention. Over 40 police officers were committed in traffic direction, warning the public, security and press control. The health service response encompassed two ambulances and two onsite medical staff. Local government reaction involved environmental health, transport and social services. The public were informed of the incident by loudspeakers, radio and word of mouth. The information focused on what to do, especially on sheltering indoors.

The outcome to humans was two admissions to a single hospital, a member of the public and a company employee, both injured in the crash. There was noticeable air pollution but only slight soil and water contamination. From an economic perspective there was major damage to the road and extensive traffic delays, but no loss of crops, livestock or production. Lessons learned included the value of rapid retrieval of information from the Chemdata system and the presence of a company technical expert enabling correct immediate action to be taken. The importance of joint press statements from responders was highlighted. Consideration needs to be given to the environmental impact of fire-fighting. If the fire had been fought in the initial stages, a considerable amount of contaminated liquid (firewater and toluene) potentially could have entered the drains, water supplies and soil.


 

 

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Contents

Preface
Part I. The Body
Part II. Health Care
Part III. Management & Policy
Part IV. Tools and Approaches
Part V. Psychosocial and Organizational Factors
Part VI. General Hazards
Part VII. The Environment
Part VIII. Accidents and Safety Management
Part IX. Chemicals
Part X. Industries Based on Biological Resources
Part XI. Industries Based on Natural Resources
Part XII. Chemical Industries
Part XIII. Manufacturing Industries
Part XIV. Textile and Apparel Industries
Part XV. Transport Industries
Part XVI. Construction
Part XVII. Services and Trade
Part XVIII. Guides