ODH Class	Fatalities/Hr
No Classification Required	0 (Oxygen concentration not less than 18%)
0	< 10-7 note 1
1	>= 10-7 but < 10-5
2	>= 10-5 but < 10-3
3	>= 10-3 but < 10-1
4	>= 10-1

Note 1: Areas that have Departmental/Divisional controls established that can demonstrate the fatality rate is less that 10-9 by engineering/safety analysis can be exempted from the ODH classification with Safety Engineering concurrence.