Concentrations of gases of any type in a confined area are regulated by OSHA standard and when the concentration exceeds the ____ of the confined area shall be avoided unless sepcified forms of protective equipment or devices are provide d.

Concentrations of gases of any type in a confined area are regulated by OSHA standard and when the concentration exceeds the ____ of the confined area shall be avoided unless sepcified forms of protective equipment or devices are provide d.