Environmental Considerations for Disinfection

As the COVID-19 pandemic continues, divers, dive operators and dive professionals must keep practicing good hygiene and proper disinfection of scuba equipment. While the pandemic has led to enhanced gear disinfection and more specific attention paid to effective disinfectant products, many divers wonder about the environmental impact of these products.  

While this is certainly an important consideration, it is difficult to reconcile. Disinfectant products are designed to kill microorganisms, and when discharged into the environment, even in diluted form, can continue to kill or cause other harm until they break down. There are a few important points to consider when planning environmentally friendly disinfection procedures:

  • Disinfectant solutions should not be discharged into the environment. Check the product’s safety data sheet (SDS) for information about proper disposal, human toxicity and more.
  • When using disinfectant solutions on scuba equipment, remember to rinse thoroughly with fresh water and allow to dry. Note that even small amount of disinfectant will be present in your rinse water, also requiring responsible disposal.
  • Make sure your chosen disinfectant is registered with the Environmental Protection Agency (EPA) as being effective against any specific or local microorganisms of concern. Look up the EPA registration in the Pesticide Product and Label System where you will be able to find whether the product can be used on scuba equipment, respirators, or other similar breathing equipment.
  • Ensure that you are able to manage the waste disposal requirements stated by the manufacturer.
  • Disinfection and sanitization are different. While disinfection is a term used to indicate that all germs have been destroyed on a hard surface, sanitization is a term used when germs are lowered to a “safe” level as described by public health standards. 

According to Green Seal’s Guidelines for Safer COVID-19 Cleaning and Disinfection, there are eight active ingredients that are considered to be safer to the environment, and  can be used on scuba equipment. These include hydrogen peroxide, citric acid, lactic acid and sodium bisulfate — but dilution requirements must be strictly adhered to.

How you dispose of chemicals is paramount. These products should not be dumped overboard into water or poured onto the ground; they should be disposed of in the manner specified on the product’s SDS. This may present a challenge when diving in a remote area or on a boat, especially a liveaboard.

For the Diver:

For personal equipment, simply sanitizing with a product that is safe for respirators and additional gear should be enough.  While scrubbing with soap and water is enough for more personal gear, disinfecting from time-to-time is never a bad idea. When disinfecting, household bleach will work. Soaking the hard, nonporous pieces of equipment for one minute in a solution of 1/3 cup of household bleach per gallon of water is sufficient to kill most harmful microorganisms. Be sure to rinse any equipment thoroughly in fresh water and allow it to dry completely.

Household use of bleach has not been shown to have detrimental effects on the environment as most of the active ingredient, sodium hypochlorite, will react with organic matter before it reaches the environment. Alternatively, if a bleach solution is allowed to stand for 24 hours, the active ingredient will break down.

For the Dive Operator:

Rental equipment should always be properly disinfected between different users. Buying an environmentally-friendly disinfectant solution is tough, but possible. Some products are ready to use, while others may require dilution with water — be sure to read instructions thoroughly before use. Be aware that there will also be variation in product availability depending on where you are located and your location’s specific environmental laws or regulations.

Unfriendly Ingredients

Of the common active ingredients in cleaning products, quaternary ammonium compounds (“quats”) are the most common. Many products that have anti-microbial, anti-bacterial or all-purpose claims — such as hand soaps, dishwashing liquids, baby care products, etc. — will contain quats.  These compounds include benzalkonium chloride, benzalkyl dimethyl or ethylbenzalkyl dimethyl ammonium, dioctyl-, octyl-, decyl-, or dodecyl- dimethylammonium chloride and even other long, complicated sounding names — such as such as n-Alkyl (C14 50%, C12 40%, C16 10%) dimethyl benzyl ammonium chloride.

When disposed of in a responsible manner, about 90 percent of quats are removed from wastewater before that water re-enters the environment. It is exceedingly important to dispose of these chemicals responsibly (such as down a drain that will lead to a wastewater treatment plant) as they can negatively affect marine life, especially algae and microorganisms.

Bottom Line

With the increased importance of disinfecting dive gear after use, there is also a need to ensure that these products don’t cause damage to the environment. Divers have a unique responsibility to care for and preserve the aquatic environment and be thoughtful about what introduce into it. As divers and dive operators work together to stop the spread of COVID-19, they should remain conscious of the products they use and their potential environmental impacts.

For additional information, reach out to Divers Alert Network’s Risk Mitigation department.