Level A Suits are used by Installation First Responders to provide the highest level of respiratory, skin, and eye protection against hazardous gases, vapors, liquids, and particulates. There are used... Level A Suits are used by Installation First Responders to provide the highest level of respiratory, skin, and eye protection against hazardous gases, vapors, liquids, and particulates. There are used by Installation HazMat Incident Response Teams (HIRT) during incident response Radiation where dangerous substances are known or suspected to cause skin toxicity, or pose immediate threats to life and health.