Final answer:
The gas free engineer is responsible for determining the safe entry of personnel into closed or poorly ventilated spaces.
Step-by-step explanation:
The gas free engineer is responsible for determining the safe entry of personnel into closed or poorly ventilated spaces. They are trained to evaluate the air quality and ensure that it is free from hazardous gases or substances before allowing personnel to enter. The gas free engineer uses specialized instruments to test the air quality and follows specific procedures to ensure safety.