Johnny is an emt with a local ambulance service. as part of his job, he is trained to recognize the existence of a potentially dangerous scene involving hazardous materials and know when to request a hazmat response. johnny's level of hazardous materials training is at the level.

First Responder Awareness.

Explanation:

Emergency medical technician (EMT) acts as a health care provider in the emergency medical services. EMT are trained to handle the emergency situations like traumatic injuries and medical issues.

Johnny acts as an EMT, and able to recognize the  the existence of a potentially dangerous scene involving hazardous materials . He is working at the first responder awareness level as it provides the oxygen therapy.

Thus, the answer is First Responder Awareness.