Lesson 109

Lesson six: Contaminated Air

Course Complete

We will discuss the air that goes into our tanks

By the end of this section, I should be able to answer these questions:

1. What are some possible causes of contaminated air?

2. What are five possible signs/symptoms of contaminated air?

3. What should I do for a diver who I suspect breathed contaminated air?

4. How do I avoid contaminated air problems?

Contaminated Air

Contaminated air contains unintended impurities. While this is actually very rare in scuba diving, scuba air must be especially pure, because trace contaminants (like carbon monoxide and oil vapor) that might be harmless at the surface can be toxic when breathed under pressure. To prevent this, compressors for filling scuba cylinders use special filters and separators to keep contaminants out of breathing air.

Possible causes of contaminated air include:

Getting a cylinder filled at an improper source (i.e., some place other than a professional dive center, resort or dive boat).
Improper maintenance of the filling system.
Very high levels of a contaminant in the source gas – more than the filters can keep out.

Contaminated air may smell and taste bad, but sometimes can be odorless and tasteless. A diver breathing contaminated air may have these signs/symptoms:

Headache
Nausea
Dizziness
Unconsciousness/unresponsiveness
Cherry-red lips/fingernail beds (though this is difficult to see underwater)

If you suspect a diver has breathed contaminated air, have the person breathe fresh air. Give emergency oxygen if available. Provide CPR if required. Contact emergency medical care. The diver should have medical attention in all cases.

Contaminated air is rare because it’s not difficult to avoid: get your cylinder filled only at reputable scuba air sources – namely, professional dive operations. Professional dive operators know how serious air quality is. They take care of their fill systems and know the value of regular air testing.

knowledge review and quiz

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