Zone 1: Hot Zone

The exclusion or Hot zone, the innermost of three areas, is the zone where contamination does occur. All people entering the Hot zone must wear the appropriate level of protection. An access control point must be established at the boundary of the Hot zone to regulate the flow of personnel and equipment into and out of the zone and to confirm that the procedures established to enter and exit are followed. The outer boundary of the Hot zone, the hotline, is initially established by visually surveying the immediate surroundings of the site and determining where the hazardous substances involved are located and where there may be:

• Drainage
• Leachate
• Spilled material

Determining the boundaries can also be provided by data from the initial site survey indicating the presence of organic or inorganic vapors/gases or particulates in air, combustible gases, and radiation or the results or water and soil sampling. In additional other factors that should be considered include the distances needed to prevent fire or an explosion from affecting personnel outside the zone, the physical area necessary to conduct site operations and the potential for contaminants to be blown from the area. Once the hotline has been determined, it should be physically secured, fenced, or well-defined by landmarks. As operations proceed, the boundary may be relocated as information becomes available from a hazard assessment or monitoring. Personal protective equipment to be worn inside the Hot zone is designated based on site-specific conditions including the type of work to be done and the hazards that might be encountered. Frequently within the exclusion zone, different levels of protection are justified. Sub areas should be specified and clearly marked as to whether level A, B, or C protection is required. The level of protection is determined by the measured concentration of substances in air, potential for contamination, and the known or suspected presence of highly toxic substances. Different levels of protection might also be designated by job assignment, for example:

• Collecting samples from open containers might require Level B protection, while for walk-through ambient air monitoring, Level C protection might be sufficient.
• The assignment, when appropriate, of different levels of protection within the Hot zone generally makes for a more flexible, effective, and less costly operation while still maintaining a high degree of safety.