Overview of NSF/ANSI/CAN 600 and Updated Health Effects Criteria

Paints and coatings are commonly used materials in potable water applications. Coatings are often used as a barrier for potable water storage tanks or as a protective layer on pipes, fittings or mechanical devices, like valves and pumps. Because the use of these products is so common across the industry, government, installers and the public want to ensure that these products are not imparting harmful levels of contaminants into drinking water. Certification to NSF/ANSI/CAN 61 provides this assurance for coatings and other drinking water system components.

NSF/ANSI/CAN 61 is the flagship standard in North America for drinking water system components. All products that come into contact with drinking water or drinking water treatment chemicals, from source to tap, fall under the scope of this standard. Forty-nine U.S. states and 11 Canadian provinces/territories currently have legislation, regulations or policies in place that require drinking water system components to comply with NSF/ANSI/CAN 61. Thus, certification to this standard provides a basis for acceptance of a product’s installation in a potable water system and ensures that the product is being evaluated to the most current regulatory requirements.

Until 2018, NSF/ANSI/CAN 61 contained two sections, Annex A and D, which included the toxicological risk assessment procedures for establishing pass/fail criteria, and the pass/fail criteria themselves, respectively. Because many other standards also included identical sections or referenced these sections in NSF/ANSI/CAN 61, the drinking water additives joint committee that oversees the standard decided to split out these sections into their own standalone standard that would serve as a reference standard for NSF/ANSI/CAN 61 and other drinking water standards. This new reference standard was designated as NSF/ANSI/CAN 600. First published in 2018 as a breakout from NSF/ANSI/CAN 61, the normative requirements under NSF/ANSI/CAN 600 were immediately effective for all products certified to NSF/ANSI/CAN 61.

The health effects criteria used for NSF/ANSI/CAN 61 (now contained within NSF/ANSI/CAN 600) are regularly updated in response to new regulatory requirements and the availability of new toxicological data. It is typical for multiple criteria updates to be included with the publication of each new version of the standard. In August 2014, Health Canada published new MAC values for toluene, ethylbenzene and xylenes. NSF/ANSI/CAN 600 (formerly Annex A of NSF/ANSI/CAN 61) requires that a substance regulated by the U.S. EPA or Health Canada be evaluated according to those assessments, without additional toxicological evaluation. The less stringent criteria previously used by NSF/ANSI/CAN 61 for these compounds were not based on regulatory values, so they were superseded by the Health Canada MAC values. Consequently, the new MAC values for these three solvents were published as updated criteria under NSF/ANSI/CAN 600. Corresponding SPAC (Single Product Allowable Concentration) values for each compound were set at levels 10-fold lower than the MAC values (Table 1).

The publication of the updated health effects criteria for these three solvents coincided with the publication of the first edition of NSF/ANSI/CAN 600, so the first edition of NSF/ANSI/CAN 600 also included these updated criteria based on the Health Canada MAC values. Given their widespread use in potable water contact products, especially coatings, NSF set a five-year implementation period for products to comply with the updated criteria for these solvents, with a compliance deadline of January 1, 2023. It is important to note that this compliance deadline applies only to the three solvents with reduced pass/fail criteria: toluene, ethylbenzene and xylenes. The other pass/fail criteria contained in Section 4 of NSF/ANSI/CAN 600 remain in effect despite their relocation from NSF/ANSI/CAN 61 to NSF/ANSI/CAN 600. In other words, all the health effects criteria within NSF/ANSI/CAN 600 were effective immediately upon publication of the standard, except for those criteria under individual implementation periods, such as those for toluene, ethylbenzene and xylenes.

The reduction in pass/fail criteria for these three solvents constituted a substantial change from the previous criteria. These solvents are widely used in coating formulations, sometimes at quite high levels, so the dramatic change in the allowable leaching levels for these solvents has meant that manufacturers have had to consider reformulation or replacement of some solvent-based coating products that are currently certified under NSF/ANSI/CAN 61. In anticipation of the January 1, 2023, deadline for their products to comply with the new criteria for these solvents, some coating manufacturers have already sought and obtained certification for new or updated coating formulations that comply with the reduced criteria.

In an effort to make these compliant coatings visible to end users in the marketplace, some of these coating manufacturers have included a statement on their product packaging, product literature and certification listing, denoting that the product “meets the applicable requirements of NSF/ANSI/CAN 600 according to the requirements of NSF/ANSI/CAN 61, including the most current health effects criteria for xylenes, toluene and ethylbenzene.” It is important to note, however, that this statement is added at the discretion of the individual manufacturer, and products that do not include it may or may not comply with the updated pass/fail criteria for toluene, ethylbenzene and xylenes. After the January 1, 2023, implementation deadline, all products certified to NSF/ANSI/CAN 61 will be required meet the new criteria, and this statement will no longer be used for any product.

Significant changes to the requirements of NSF/ANSI/CAN 61 can have major impacts on the affected product industry, and when the impact is large, it is common for a longer implementation time frame to be set for manufacturers to meet the new requirements. Such a strategy allows for this critical drinking water health effects standard to remain appropriately rigorous given the current state of toxicological knowledge, while providing enough time for manufacturers to update their product lines and still keep certified products on the shelves. Additionally, users who may be looking to purchase products that comply with the new solvent criteria in advance of the deadline are given the ability to find these products by looking for the statement declaring compliance with the new criteria.