Anticipating the entry into force of the OPRC-HNS Protocol (Protocol on Preparedness, Response and Co-operation to pollution incidents by Hazardous Noxious Substances) in June 2007, Oil Spill Response & East Asia Response Limited (OSRL/EARL) initiated a HNS study (focusing mainly on petrochemical floaters), exploring the issues involved in providing an effective HNS spill response. This paper aims to discuss the development of a novel site entry protocol for responders.

Health and safety of personnel is always of the utmost priority during a spill response. Due to the vast range of chemicals and their associated behaviours, numerous considerations have to be taken into account, especially when more than one substance is involved: Some chemicals can react with each other or with sea water, creating a more hazardous environment (fire, explosion, toxic fumes, etc) and the behaviour of the numerous products transported by sea can greatly differ when they are spilled into the marine environment. It is therefore essential to make an appropriate assessment, having integrated safety protocols and well trained response teams before proceeding to the site of the incident.

In addressing the safety aspect of a HNS response, OSRL/EARL has developed a site entry protocol based on the "Controlling Compound" methodology. The approach of this protocol is to set all gas monitoring devices based on the most hazardous compound when there is a mixture of chemicals spilled. The rationale for this is that the identity of the vapours in the air following a "cocktail" spill is often unknown. Even if they are known, the composition ratio of the gas mixture is definitely not constant in an open environment. As a result, the conventional method of setting alarms in a Photo-Ionisation Detector (PID) is not applicable. This method is not widely practiced and this paper proposes to explain the approach, advantages and limitations of this protocol for responding to HNS spills.

1. Introduction

There is a large quantity of dangerous goods and hazardous material transported by sea each year. Hazardous Noxious Substances (HNS) including products of oil refineries are usually transported in specialized chemical tankers, in bulk chemical tankers carried by other vessels, or as packaged goods. These chemicals can enter the marine environment as a result of an accident or can be a deliberately released. Accidental releases can occur as a result of natural disasters, human fault or due to technical and mechanical failure during transfer and storage. Intentional releases could include acts of war, terrorism, dumping of chemical waste and sabotage. HNS spills of larger size could also be caused by vessel groundings, collisions, fire, explosion, etc.

Chemicals might pose fire and health hazards depending on their physical and chemical properties. Due to the wide range of chemicals and their associated behaviours, there are many indicators on the Material Safety Data Sheet (MSDS) to be considered before approaching a spill. Thus, guidelines on the setting up of the gas monitors, the appropriate type of Personal Protective Equipment (PPE), etc are important. Even though there have been numerous studies on chemical spill response being conducted, the detailed site entry protocol for responders is not always available. In this paper, the site entry protocol using the "Controlling Compound" methodology will be discussed.

2. Chemical Classification

The chemical behaviour classification is important during a spill response in an aquatic environment. It will not only determine the fate of the chemical, but the response strategy as well. Chemicals behave differently when they are in water and their behaviours can be classified using the International Maritime Organization (IMO) fate code.

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