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.

You can access this article if you purchase or spend a download.