2.1. First phase area isolation actions

In HNS incidents where there is a risk of flammable, explosive, toxic or irritative cloud or vapors, dangerous area has to be isolated from the maritime (and air) traffic. In general only Search and Rescue Units (SRU) with capability to enter dangerous atmosphere are permitted to enter the restricted zone only with RCC acceptance.

2.2. Continuous risk assessment

The information to update risk assessment and maintaining the situation awareness are essential when defining the restrictions to respond the actual hazards on-scene. The continuous update process of the restriction and working areas should be based on the latest risk assessment and weather conditions (e.g. wind direction, weather forecast).

2.3. Assessment of the HNS impact

The restriction area for maritime and air traffic (NO-FLY zone; e.g. possible hazards, RPAS operations, rescue operations) should be determined based on the information of the incident. Defining of the area should be based on the information and identification of the HNS involved. Determination is done by formulating circle (or hemisphere if there is a NO-FLY zone) area around the distress vessel.

In situation where information of the HNS involved is not available at the first phase, radius of the immediate restriction area should be at least 2NM.

The effect of the weather and weather forecast as well as possible distress vessel maneuvers should be taken account when determining the area for further restrictions. From the point of release the gas cloud will move in the wind direction in a triangular area. The area defined from approximately 30° angle from the release is the limit of the hot zone and the 60° angle defines the warm zone limit. If there is a risk of hazardous zone to expand to concern third parties, e.g. on land – continue procedures with national land based alarm plan.

2.2. Defining the restriction area

Risk assessment considering HNS in the area should be based on the support of the experts, predictive tools, databases, use of the cargo plan etc. available information. Additional information and situation reports (SITREP) from the distress vessel (DV) (cargo information, hazards and alterations), rescue units on-scene and other maritime or air traffic will complete the situation awareness. RCC should continuously update the available HNS information.

The established area restrictions should be updated based on the performed risk assessment by increasing or reducing radius and formulating the shape of the restricted area. Definition of the area is done by means of measurements and by consulting experts for the drift estimations and calculations.

DV, SRUs, VTS and ATS should be informed by the RCC considering the updates and possible cancellation of the restrictions in the area.

2.3. Information

Maritime traffic should be regularly informed considering the restriction area with GMDSS PAN-PAN or MAYDAY RELAY messages. Contact Vessel Traffic Service (VTS) (and Air Traffic Service (ATS)) concerning the restriction of the areas. Contact relevant authorities and/or media for the issuance of warnings, access restrictions and general warning to the people in the risk area if needed.

SRUs approaching the area require the latest information of the restrictions and isolation process. The restriction area should be under surveillance of authorities (RCC and SRUs with surveillance capability) and maritime traffic approaching the area should be informed and rerouted if necessary. The area restriction surveillance should be performed by authorities and vessels with capacity to monitor the area isolation.

2.4. Determining areas for SAR operation

The three-level working zone system of area designation:

2.4.1. Hot Zone

The Hot Zone is an area where the risk for contamination and probability for exposure to hazardous substances is highest. In the first phase the Hot Zone can be the radius around the DV or location onboard DV, based on HNS identification, measurements and calculations. The highest level of Personal Protective Equipment (PPE) is needed in this area.

2.4.2. Warm Zone

The Warm Zone is an area surrounding the Hot Zone. This area is a transition area between Hot Zone and the Cold Zone. The Warm Zone can be the radius around the DV or location on board the DV, based on HNS identification, measurements and calculations. If decontamination process is planned to execute onboard SRU or other vessel on-scene, vessel is usually positioned in the Warm Zone or in the border of the warm and the cold zone if possible. The warm zone and the cold zone are then established onboard the SRU to ensure effective decontamination process.

2.4.3. Cold Zone

The Cold Zone is an area outside the Warm Zone. The Cold Zone is free from contamination and may be used as holding and support area. When the Warm Zone and the Cold Zone are established onboard the SRU, service and treatment facilities are located in the Cold Zone.  The cold zone defines the outer safety cordon i.e. limit of the restricted area which should be under surveillance to prevent unauthorized entry.

2.4.4. Entry point

Prepare to arrange controlled access to the restricted area for the rescue vessels. Entering to the warm zone should be upwind and allowed only for vessels with capacity to perform rescue operations in the hazardous atmosphere. Weather and weather forecast (e.g. changes of wind direction) should be taken under consideration when establishing the entry (and exit) point to the restricted area.