Which is a disadvantage of positive pressure supplied air respirators?

Answer: C — Requires egress to use the same path as entry

The disadvantage of positive pressure supplied air respirators involves the requirement for egress through the same path as entry. This means that, in the event of a dangerous situation or emergency, individuals relying on these respirators must navigate the same route they took to enter the hazardous environment. This could potentially be unsafe if conditions change or if there are obstacles that were not present upon entry, as it limits the options for escaping from a hazard. In many hazardous situations, having a more flexible escape route can be crucial for safety. Lacking this flexibility can cause delays and increase the risk of exposure to toxic substances, thereby compromising the safety of personnel utilizing these respirators. While increased weight, high cost, and limited air supply may also be viable concerns associated with positive pressure respirators, they do not directly impact the immediate ability to exit safely after entry in the same way that the requirement to use the same egress path does.