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Toxicity Hazards Concentration versus Lethality per Literature Chlorine
Probit Correlations

1000.0
US Coast Guard Report CG-D-38-79 (1979)
Concentratoin for 1 Hour Exposure (ppm)
World Bank Technical Paper 55 (1988)
RVIM "Purple Book" CPR 18E (2005)
HSE OGP Report 434-14.1 (2010)
RVIM Report 2015-0102 (2015)
ERPG-3

100.0

10.0
0.001 0.01 0.1 1
Lethality

Figure 3-4 Chlorine Concentration versus Lethality for Several Published Probit Models

3.15 Asphyxiation

Hazards with gas or vapor inhalation also includes asphyxiation (Table 3-4). Relatively non-toxic chemicals may pose
an asphyxiation hazard, particularly for release within an enclosed process area. The oxygen content may be estimated
using Equation 3-5 (assuming air at approximately 21 volume % oxygen):

Average Percent Oxygen = 21 (1 – CIndoor / 1,000,000) Equation 3-5

where CIndoor is the concentration of released material within an enclosed area in ppm by volume. This simple equation

assumes the enclosed volume is well mixed such that the average concentration may be used to represent the hazard.
 Faulty judgment and disorientation occurs at 12-16% oxygen which may be a reasonable level to consider as
severe impact in Risk Analysis.
 Less than 19.5 percent oxygen often represents the level needed for supplying breathing air (this value, for
example, is required by the US OSHA).

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