You get to pick ONLY three (3) pieces of data about a chemical you have responded to. You know the chemical, so what would the three (3) pieces of data you would want to know be and why? Here are my three and why…
#1 – Vapor Pressure – this tells me the volatility of the chemical and how easily it will go from its liquid state to vapor/gas state. The #1 way we get exposed to chemicals is INHALATION and most HAZMATs are shipped/stored as liquids. However, once the container is breached, the liquid (if it has a VP>85 mm hg) will present an Inhalation Hazard.
#2 – IDLH level – This is the GAME CHANGER and at this level (even if not at IDLH, but the potential exists) we can ONLY respond in an SCBA in the Positive-Pressure mode. This single data point also informs me of the toxicity and hazards associated with my chemical. My scale is anything less than 500 pppm IDLH is an “Oh Boy” moment!
#3 – The LEL of the gas/vapor – This is key because responding to a release that can present a flash fire/explosion hazard requires a different type of PPE than, for example, a traditional HAZMAT response to a corrosive/toxic chemical. Walking into an uncontrolled release of a flammable liquid or gas WIHTOUT knowing this data point can result in responder deaths.