Chlorine is EXTREMELY HAZARDOUS, with an IDLH of 10 ppm and a TLV of 0.5 ppm (just above the odor threshold for most).
Chlorine is heavier than air (VD > 2.5), and when released, it forms a greenish-yellow gas with a pungent, irritating odor that follows the terrain at ground level.
The mean odor threshold for chlorine lies between 0.2 and 0.4 ppm.
Chlorine is a NON-FLAMMABLE gas; however, it is a powerful oxidizing agent, reacting explosively or forming explosive compounds or mixtures with many common chemicals.
Chlorine immediately reacts with both organic and inorganic materials it comes into contact with to form chlorides.
The primary route of exposure is INHALATION.
Chlorine is very volatile, with a Boiling Point of -29°F. So, although it is shipped as a liquefied gas under pressure, once the primary containment is breached, it will quickly become a GAS.
The Vapor Pressure of Cl2 is 6,450 mm hg @ STP. Remember, BP and VP have inverse relationships. As BP goes down, VP goes up, and vice versa.
An excellent standard to follow is that water at STP has a VP of 25 mm hg and a BP of 212°F. Cl2 is the opposite: it has a high VP (6,450 mm hg) and a Low BP (-29°F).
