Tennessee Wastewater Operator Practice Exam

At what concentration does chlorine become fatal after a few breaths?

1. 500 mg/L

2. 750 mg/L

3. 1000 mg/L

4. 1500 mg/L

The correct answer is: 1000 mg/L

The concentration of chlorine that becomes fatal after just a few breaths is at 1000 mg/L. At this level, chlorine can cause severe respiratory distress and damage to the respiratory system upon inhalation. Chlorine gas is a highly toxic substance, and exposure to high concentrations can lead to pulmonary edema, choking, and even death very quickly. In understanding the safety limits of chlorine exposure, it is essential to know that concentrations below this level can still be hazardous but are generally less immediately life-threatening. Lower concentrations could lead to symptoms such as coughing, throat irritation, and shortness of breath, but do not carry the same level of acute risk as 1000 mg/L. Therefore, this specific concentration is a critical threshold for operators to recognize in ensuring safety when handling or working near chlorine in wastewater treatment facilities.