Control Zones and Decontamination

Key Concepts

Initial Actions for Hazardous Materials Incidents

• Size-up: Perform as soon as the call is received; start immediately at the scene if not pre-planned.
• Establish Command: Set up a command structure and a safety role.
• Isolate: Use the Emergency Response Guide (ERG) to gather information.
• Victim Management: Direct victims to a safe location and prevent them from leaving the scene.
• Evacuation: Think of how to evacuate uncontaminated persons from the hazard area.

Control Zones

• Isolation Perimeter: Outer boundary to prevent public entrance; enforced with police cooperation.
• Initial Isolation Distance: Circular area for evacuation in all directions from the spill or leak source.
• Protective Action Distance: Downwind distance for evacuation or shelter-in-place decisions.
• Hot Zone: Area with the highest level of danger; PPE is always required and no public access.
• Warm Zone: Contamination reduction zone; PPE and decontamination required.
• Cold Zone: Support zone; no PPE required; command post and support functions located here.

Hazard Control Zones

• EPA Terms: Exclusion Zone (Hot Zone), Contamination Reduction Zone (Warm Zone), Support Zone (Cold Zone).
• Decontamination Corridor: Set up within the cold zone to create the warm zone; crucial for proper decontamination.

Decontamination Methods

General Methods

• Wet Decontamination: Washing with solutions or flushing with water; collect runoff water.
• Dry Decontamination: Scraping, brushing, and absorption; minimal runoff.
• Physical Decontamination: Removing contaminants mechanically.
• Chemical Decontamination: Using chemicals to neutralize or degrade contaminants.

Specific Decontamination Techniques

• Dry Techniques: Vacuuming, Absorption, Brushing/Scraping.
• Wet Techniques: Dilution, Washing.
• Physical: Adsorption, Evaporation.
• Chemical: Solidification, Chemical Degradation, Neutralization.

Decontamination Processes

Emergency Decontamination

• For entry team personnel in life-threatening situations.
• Quick removal of contaminants without formal decontamination line.

Technical/Formal Decontamination

• Slow and methodical; thorough removal of contaminants from responders and equipment.

Gross Decontamination

• Rapid removal of worst contaminants using large amounts of water.
• Used in emergencies, mass decontamination scenarios.

Patient Decontamination

• Disinfecting patients for medical care; ambulatory and non-ambulatory processes discussed.

Setting Up Decontamination

• Decontamination corridor must be established prior to hot zone entry.
• Consider site accessibility, terrain, lighting, water supply, and wind direction.
• Ensure privacy and proper disposal of contaminated items.

Definitions

• Contamination: Hazardous material transfer to various entities.
• Decontamination: Removing hazardous materials to prevent spread.
• Exposure: Coming in contact with hazardous materials.
• Hazard: Type of harm from hazardous materials.
• Primary Contamination: Direct transfer in the hot zone.
• Secondary Contamination: Contamination spread outside the hot zone.
• Surface/Permeation Contamination: Contamination on or within surfaces respectively.