Florida Drinking Water Operator "B" Practice Test

At what concentration of chlorine (ppm) can death occur after a few deep breaths?

1. 500 ppm

2. 700 ppm

3. 1,000 ppm

4. 1,500 ppm

The correct answer is: 1,000 ppm

Chlorine is a potent oxidizing agent that can be harmful, even at relatively low concentrations. The correct concentration at which death can occur after just a few deep breaths is approximately 1,000 parts per million (ppm). At this level, exposure to chlorine gas can lead to severe respiratory distress, edema, and other fatal physiological responses. At 1,000 ppm, chlorine interferes with the body's ability to properly oxygenate blood, causing significant damage to lung tissue and potentially leading to respiratory failure. This concentration is well above the threshold where individuals may experience immediate health effects, such as coughing, throat irritation, and shortness of breath, but it can escalate quickly to life-threatening situations with continued exposure. The concentrations mentioned in the other choices are still dangerous but typically will not cause immediate death so rapidly as at 1,000 ppm. For instance, while 500 and 700 ppm can cause serious health effects, the timeline to severe health consequences is generally longer than with 1,000 ppm. Similarly, while 1,500 ppm represents a very high concentration and would be expected to be fatal, the specific threshold for quick fatality, particularly after a few deep breaths, is identified around the 1,000 ppm mark.