Chemsheet

The actual process of arriving at a decision in case of an accidental spill varies greatly from spill to spill. In most cases such decisions will be reached based on experts' opinions, financial aspects, technical aspects and agreed policies. The decision whether or not to respond to an accidental spill at sea will be a balance between, on the one hand the extent of the threat to people or to the marine environment and, on the other hand, the costs that are involved in responding to reduce that threat. This needs a systematic approach to hazard assessment.

The gravity scale for accidental spills is to be primarily developed in order to improve the situation in which there is no objective way of determining the gravity of an accidental spill. Another reason for designing the gravity scale for accidental spills is to have a tool, which can be used to make a clear distinction between the different levels of response organization required as a function of the gravity of the accidental spill. The gravity scale for accidental spills has to give an objective basis to determine the overall seriousness of an accidental spill at sea. This scale can also be used in communication with decision-makers, the media and the public in general to explain the seriousness of the accidental spill objectively.

The gravity scale for accidental spills may assist the responsible authorities in judging the gravity of an accidental spill at sea and provide a means whereby the general public and the press can more easily arrive at a reasonable assessment of the true nature of accidental spills. The gravity scale for accidental spills is to give an objective basis for hazard quantification in a single scale value. For the on duty officer, the media and the officials the most understandable way to express the gravity of an accidental spill is in a single scale value. Similar to the Beaufort scale, which expresses the different wind forces, non-experts prefer a single scale value for all the different hazards.

On the basis of the gravity scale value for an accidental spill the required level of response organization can be determined. The gravity scale for accidental spills has to give an indication of the extent of imminent damage if no measures are taken, facilitating the level of intervention, which is proportionate to the seriousness of an accidental spill. The scale evaluates and describes the seriousness of the situation so that the appropriate response organization can be alerted and decisions can be made as quickly as possible to enable prompt and effective action to be taken. The officer on duty determines the required level of response organization and the level of hazard by reference to the scale. This gravity scale for accidental spills also serves to compare one spill with another.

In order to determine the gravity of a spill situation the on-duty officer, as a "first aider", needs a kind of degree-meter to quickly determine the seriousness of the situation. Using this degree-meter he must be able to weigh up the gravity of the overall situation. The on-duty officer, as a first aider, is in charge until responsibility is handed over to the on-shore co-ordinator.

Up to now, the judgement of experts involved has been focused on how to determine the seriousness of an accidental spill. Depending on the expert's discipline and personal opinion the hazard aspects (such as bioaccumulation, aquatic toxicity, explosiveness, etc.) are given different weights. This means that the outcome of a hazard assessment could vary as it depends on the expert carrying out the assessment. For the discussion within IMO on the problem of liability for hazardous substance spills there is a need for criteria to assess recovery classes, for substances in packaged forms and in bulk and generally for cargoes in ships, which have sunk. In order to arrive at these recovery classes, a scoring procedure is needed which yields objective results independent of the user. The recovery of substances posing threats, either to human beings/property or to the marine environment, is recommended in all cases where such recovery is technically and economically feasible. The relationship between costs and the gravity of the spill could be used to determine the economic feasibility of recovery. There is a need for a subjective and reproducible procedure to determine the gravity of an accidental spill.

Chemsheet is intended to support the gravity scale. The gravity scale does not evaluate:

1. The seriousness of the separate hazard aspects,
2. Whether these hazard aspects affect human beings or the marine environment,
3. The amounts passing into the different compartments (air, water surface, water column and sea floor) and
4. Other relevant information, which could be needed to identify the most, appropriate response actions.

Therefore, chemsheet has been developed to provide a more adequate diagnosis (situation analysis).

Situation analysis of hazard with regard to a released hazardous substance or to its potential release is critical because the adverse effects may be catastrophic to human beings, property and the marine environment. Information on such hazards are often difficult to obtain or to interpret even in the long term let alone the short term need for decision making in the initial stage of an accidental spill at sea.

The level of gravity of an accidental spill depends on various parameters. Some of these parameters are objective (type and quantities of the substances concerned, the place of release) while others are more subjective (weight given to hazard aspects in the process of decision-making, media reaction, etc). Again, the rates of various processes influence the impact of the spilled substance while these rates in turn depend on spill characteristics, environmental conditions and physical and chemical properties of the released compound. Based on the situation analysis, three types of parameters may be distinguished which are determining factors to assess the gravity of an accidental spill:

1. Effects of the spill (or the near miss): hazard aspects to human beings/property and hazard aspects to the marine environment, which depend on the substance released;
2. A parameter characterizing the behaviour of the released substance, being essentially a function of the quantity and type of the substance concerned;
3. The parameters characterizing the place of release with regard to the presence of human beings/property or sensitive marine organisms.

The hazard aspects and physical behaviour of the substance released should be known or determined by means of this diagnostic tool which in its turn will provide the necessary information for ultimate decision-making on possible counter pollution measures. The following determining factors (see above) to assess the gravity of an accidental spill, to be noted down in a checklist, should be sufficient for this diagnostic model:

- name of substance;

- quantity;

- place of release.

This information is often the only information available in the initial stage of a spill. Chemsheet is an analytic and synthetic tool in the event of accidental spills, to serve as an aid to the decision-making team, which it is not, intended to replace. It should help policy-makers to understand the complex problem of hazardous substances in the marine environment. Chemsheet will compel its users to give full consideration to all consequences of a given spill; it will identify what is important and present this information to assist decision-making. Chemsheet will present relevant information in a useful way for the decision-maker(s). The system will identify and characterize the level of seriousness of a spill and characterize the relevant hazard aspects. The possible hazard aspects will be sorted out, identified, analyzed separately and presented in an orderly way, with an evaluation of the relevant hazard aspects.

Chemsheet, is to be an aid to decision-making in which the process of reaching a decision may be assisted in an orderly and systematic way.

The critical components of the possible hazard aspects have to be sorted out, identified, analyzed separately and presented and comprehensively evaluated in an easily understandable and orderly way. Thus the model will provide a complete hazard assessment of the spill. The model will evaluate the overall threat, the threat to human life and property and the threat to the marine environment entailed by a given spill or potential spill by characterizing the individual types of threat.

In summary:

• • Chemsheet provides a hazard analysis of an accidental spill;
  • Chemsheet indicates (1) the overall threat, (2) the threat to human life and property and (3) the threat to the marine environment posed by a given (or potential) spill;
  • Chemsheet presents the seriousness of the separate hazard aspects (toxicity by inhalation, explosiveness, flammability, aquatic toxicity, bioaccumulation, persistence, radioactivity, corrosiveness and carcinogenicity);
  • Chemsheet determines the amounts passing into the different compartments (air, water surface, water column and sea floor);
  • Chemsheet is suitable for computerization.

Decision-making requires, besides financial and social aspects, additional information on quantitative division of the mass of the spill over the four different compartments (the air, the water surface, the water column, the sea floor) that can be polluted by a chemical spill and the relevant hazard aspects and the seriousness of these hazard aspects.

The actual process of arriving at a decision in the event of an accidental spill varies greatly from spill to spill. In most cases such decisions will be based on experts' opinions, financial aspects, technical aspects and agreed policies. It is Chemsheet that provides the needed additional information and it presents that information in an objective way. Chemsheet does not recommend decisions: it simply presents this necessary additional information in a useful way that will aid decision-making. Chemsheet is a tool to analyse the spill situation, to serve as an aid to the decision-making team, and is not intended to replace them. With the information obtained through Chemsheet it becomes possible to formulate all relevant response methods to cope with the spill under consideration.

It is then that decision-makers are made aware of all the consequences of a given spill and the possible response pollution measures.

It is imperative that all the information for taking decisions becomes available with the shortest possible delay and with minimum effort.

This requirement calls for computerization of the system and computerized access to substance databases.

Chemsheet is an aid to the process of translating a hazard assessment into orderly and systematic information required for decision-making with regard to response to an accidental spill. Up to now various hazard classification systems have been used, some of which are difficult for non-experts to interpret.

Chemsheet is an aid to the process of translating a hazard assessment into orderly and systematic information required for decision-making with regard to response to an accidental spill. Up to now various hazard classification systems have been used, some of which are difficult for non-experts to interpret.

The aim of Chemsheet is that the critical components of the possible hazards are sorted out, identified, separately analyzed and that the hazards are presented in an easily understandable and orderly way. A rapid hazard assessment model in the initial stage of an accidental spill makes the necessity of having standby of (expensive) chemical experts superfluous.

The tool provides a complete hazard assessment of the accidental spill. It evaluates the overall threat, the threat to human life and property and the threat to the aquatic environment entailed by an actual spill or potential spill. The model objectively characterizes the type of threat based on internationally agreed properties. Chemsheet does not predict the probability of the effects; it only considers the hazards and their potential seriousness. This means that Chemsheet should be used in the initial stage of a spill. In the developed stage of an accidental spill experts are still needed, but they can concentrate on decision-making and devote less attention to gathering and evaluating information.

Chemsheet assesses the behaviour of the pollutant. In the event that several substances are involved in one accidental spill, the model also presents a priority rating attached to the different substances which gives an indication of the relative potential danger associated with each substance released. Nine different hazard aspects are presented by means of separate scores similar to the gravity scale values for accidental spills, indicating the seriousness of each hazard aspect. Chemsheet gives a clear indication as to whether the substance is hazardous either to human life or to the marine environment or both, and it indicates the degree of hazardousness.

Chemsheet identifies what is and what is not important. In addition, it may help the responsible authority, which has already made up its mind, by supporting a particular viewpoint.

The output of Chemsheet consist out of

1. The behaviour classification (BC);
2. The relative scale values to present the nine hazard aspects;
3. The gravity scale value for an accidental spill;
4. The relative scale value to present the hazard aspects to human beings/property and to the marine environment.

A substance is chosen from a drop down list, based on name or UN number. The sheet then lists all relevant information about the substance, such as:

Physical properties

Safety aspects

GESAMP hazard profile

Adequate preparation is the most important aspect in an effective response to accidental spills; arrangements that could enhance an adequate response are essential in order to be able to act effectively when an accidental spill occurs. With the help of the Chemsheet a list can be made of priority substances of which the risk in the marine environment is the greatest.