Stengle's Positivstellensatz

Packing Group	Hazard Zone	Vapor Concentration and Toxicity
I	A	$V\ge 500L{C}_{50}$; $L{C}_{50}\le 200\frac{mL}{m^3}$.
I	B	$V\ge 10L{C}_{50}$; $L{C}_{50}\le 1000\frac{mL}{m^3}$ The criteria for Packing Group I. Hazard Zone A are not met.
II	C	$V\ge L{C}_{50}$; $L{C}_{50}\le 3000\frac{mL}{m^3}$ The criteria for Packing Group I, Hazard Zones A and B are not met.
III	D	$V\ge .2L{C}_{50}$; $L{C}_{50}\le 5000\frac{mL}{m^3}$ The criteria for Packing Groups I and II, Hazard Zones A, B and C are not met.
Note 1: V is the saturated vapor concentration in air of the material in $\frac{mL}{m^3}$ at 20°C and standard atmospheric pressure. Note 2: A liquid in Division 6.1 meeting criteria for Packing Group I, Hazard Zones A or B stated in paragraph (a)(2) of this section is a material poisonous by inhalation subject to the additional hazard communication requirements in 49CFR 172.203(m)(3), 49CFR 172.313 and Table 1 of 49CFR 172.504(e) of this subchapter. These criteria are represented graphically in Figure 1:
File:Class 6 Hazard Zones.png