Gas vs. Bleach: Why Bleach is NOT the Safer Choice 

Chlorine is the most economical and effective method of disinfecting potable water. Additionally, both the US Environmental Protection Agency (EPA) and the World Health Organization (WHO) requires 2-5 parts per million (ppm) chlorine residual in potable water systems to ensure safe drinking water. The form of chlorine that is safest to use is a subject of debate, which brings us to the topic of today’s blog; which is safer, Chlorine Gas or Sodium Hypochlorite? 

There are multiple myths surrounding bleach being safer than gas chlorination.  

  • Myth: chlorine gas is detrimental to human health and bleach is not. 

As we pointed out in our last blog, chlorine has a long history of effectiveness in eliminating water borne pathogens and disease. Further, the active component in bleach that does the disinfecting work is chlorine. It takes the same amount of available chlorine to disinfect water whether you are using chlorine gas or sodium hypochlorite. Therefore, bleach is NOT safer to human health.

  • Myth: Handling bleach is safer than handling chlorine gas. 

Chlorine gas is packaged and stored in low pressure cylinders where it will remain stable for long periods of time. It is then fed into water supplies via vacuum feed systems. Whenever vacuum is lost, the flow of gas is shut off, keeping the gas inside the cylinder. Bleach is fed into water supplies from tanks via chemical feed pumps. Deliveries of bleach are more frequent due to rapid loss in strength. Great care must be taken to ensure that no other chemicals are added to bleach tanks as violent chemical reactions can occur. Accidents are more likely to happen due to the increased frequency of deliveries. Peristaltic chemical feed pumps are the favored choice due to the off-gassing nature of bleach. When peristaltic tubes fail, bleach is spilled. Therefore, bleach is NOT safer to handle than chlorine gas

  • Myth: Chlorine gas is more dangerous than bleach. 

According to the Coalition to Prevent Chemical Disasters, five chlorine gas incidents were recorded at water and wastewater sites since 2021. Of those five incidents, there were no injuries and no harm to the public. In contrast, there have been two incidents involving bleach at water treatment plants in the last year alone. With those bleach incidents, there were serious injuries that involved hospitalizations. This data challenges the misconception that gas chlorine is more dangerous. While the EPA regulates gas heavily, there is no regulation on bleach. Clearly the potential danger to Water Operators and the public is equally real with bleach. The difference is that with chlorine gas, operators are trained to mitigate risk, the all-vacuum chlorination equipment is designed for safety, and the regulations require safety protocols to be followed. Therefore, chlorine gas is not more dangerous than bleach. Further, bleach should be regulated to mitigate accidents. 

Conclusion

Superior gas chlorination systems are equipped with multiple layers of safety including automation AutoValve, atmospheric gas detection (SLD-1 & SLD-2), and a Superior exclusive Safe-T-Close, emergency shut off device (ESD). Additionally, strict regulatory controls, emergency planning, and modern equipment design further reduce the risk of chlorine gas accidents. Bleach lacks these rigorous safety systems and poses a greater risk of chemical burns, eye injuries, inhalation injuries, destroyed clothing, and damaged equipment.  

The evidence is clear: bleach is not the safer option for water disinfection. Modern gas chlorination, when managed with Superior safety measures and regulations, poses minimal risk to human health, water operators and public safety. 

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