In September, NSF International released its first standards language dedicated to pool chemicals.

The latest edition of NSF/ANSI Standard 50, which covers pools, hot tubs and other recreational water facilities, features a new addendum specifically on this topic.

Chemical manufacturers will be most affected by the new addendum. However, the goal is to help ensure the safety of pool and spa users, and help industry professionals feel more confident about the chemicals they offer.

The addendum covers the effects of skin contact with chemically treated pool and spa water, as well as inhalation exposure from chemicals that are in the air around pools and spas in a gaseous form. The potential health effects from orally ingesting chemically treated water are covered in NSF/ANSI 60.

Standard 50’s new section is written to provide a basis for evaluating chemicals that are sold exclusively for pool and spa use. It will cover products for residential and commercial pools.

To receive NSF listing for the chemicals, manufacturers must meet the specifications of this new language.

Such listing could be used by consumers as a decision-making tool for purchasing chemicals, said Blake Stark, the business unit manager, Water Treatment Chemicals, at NSF International.

The updated standard will apply in states that adopt it. NSF expects it to eventually become regulation in most states.

To comply with the standard, manufacturers must provide specified information on the chemical labels, including maximum dosage rates, the chemical name, product name and lot number (or production identifier), company name and production facility designation. The requirements are similar to those specified in NSF 60, Stark said. The chemicals also must be tested to fall within certain exposure parameters.

Toxicity screening will occur in NSF’s lab to determine the concentration level of the chemical in water when maximum dosages are used. To determine if and how a chemical should be evaluated after the initial screening, the third-party certification organization set a concentration baseline threshold for chemicals of 10 micrograms per liter of water, or 10 µg/L. It is equal to 10 parts per billion of the respective chemical in pool water.

Chemicals with a concentration of less than 10 µg/L don’t require further evaluation

Substances whose toxicity data isn’t available must be shown in the lab to not exceed concentrations greater than 10 µg/L when the maximum dosages supplied by the manufacturer are followed.

“For states or regulatory districts where NSF 50 certification is a requirement, chemicals in this category would only be eligible for use at very low levels in swimming pools,” Stark said.

Chemicals registering higher concentrations than 10 µg/L will be put through a three-step process to determine if the exposure falls at or below safe levels.

NSF certification must be generated through the organization’s laboratory. Manufacturers can submit chemical samples directly to the lab or have samples collected during field audits of their facilities.

Standard 50 should be familiar to most in the pool industry because it has been in continuous use since 1977, when NSF, then known as the National Sanitation Foundation, combined several individual standards for pools into one.