When responding to a chemical emergency, ambient oxygen measurement is frequently used to assist in specifying the level of PPE required for worker safety. An oxygen deficient atmosphere, on a vol%...

When responding to a chemical emergency, ambient oxygen measurement is frequently used to assist in specifying the level of PPE required for worker safety. An oxygen deficient atmosphere, on a vol% basis, is defined by NIOSH/OSHA as (select one)

1) 25 or less

2) 19.5 or less

3) 15 or less

4) 12.5 or less

5) 10 or less