Ask the Expert Question-and-Answer Archive

by Ron Joseph

March, 2005

Zero VOC Coatings - Solvent and Waterborne

Q. (1) If glycols (ethylene or propylene glycol) are not exempt for VOC, is it reasonable to say there are no zero VOC aqueous coatings which are freeze-thaw stable?
(2) Likewise, as all amines are non-exempt (AMP-95, MEA), is it also impossible to have an alkali-swellable thickener in a zero VOC aqueous coating?
(3) As almost all sovent coalescents are not exempt, is it also the case that aqueous paints requiring coalescence are rarely, if at all, zero VOC aqueous coatings?

A. Unfortunately I am not a paint formulator and therefore cannot answer your questions directly. The fact is that if any coating ingredients are volatile per EPA Method 24, but are not on the list of exempt solvents (compounds) then they must be counted as VOCs.

The next issue relates to the meaning of zero VOC. I have searched the EPA website high and low, but found no defnition of "de minimus" for VOCs. However, OSHA has defined "de minimus" for reporting under Section 313, and to the best of my knowledge the EPA accepts the same limits for reporting VOC and HAP on an MSDS.

The definition is as follows:

Under section 313, a chemical does not have to be counted towards threshold determinations and release and other waste management calculations if it is present in a mixture below a certain concentration. This is known as the section 313 "de minimus" concentration in mixture. When the section 313 rule was developed, EPA adopted the de minimus percentages from the Occupational Safety and Health Administration's (OSHA) Hazard Communication Standards (29 CFR 1910.1900) because much of the information that industry would have relating to chemicals in mixtures would most likely be from the material safety data sheet (MSDS) on that mixture. The OSHA de minimus limitation is 0.1 percent if the chemical is a known or suspect carcinogen by virtue of appearing in one of three sources: 1. National Toxicology Program (NTP), "Annual Report on Carcinogens" (Latest Edition); 2. International Agency for Research on Cancer (IARC) "Monographs" (Latest Edition); or 3. 29 CFR 1910, Subpart Z, Toxic and Hazardous Substances, Occupational Safety and Health Administration.

The de minimus limitation is 1.0 percent for chemicals that do not meet the above OSHA carcinogen criteria. The carcinogen designation in the list of chemicals relates to any chemical that the Agency determined met the above OSHA criteria for the 0.1 percent de minimus limitation. Certain metal compound categories have two de minimus limitations. For example, hexavalent chromium compounds and inorganic arsenic compounds meet the OSHA carcinogen criteria, while trivalent chromium compounds and organic arsenic do not meet the OSHA criteria. Table C-1 shows the specific bases for which the individual chemical was designated as a known or suspect carcinogen. This list was updated for the 1999 TRI Public Data Release, based on a review of the most current NTP, IARC, and OSHA sources.

If volatile ingredients (per EPA Method 24) are added in de minimus quantities, such as <1% (by weight) for non-carcinogens or <0.1% (by weight) for carcinogens then they might not need to be counted as VOC. In any case, under OSHA the raw material supplier is not required to list the chemical as a "Hazardous Ingredient".

In summary: If a coating contains very small quantities of VOC which are present below the de minimus values, then you can consider the coating to be zero-VOC.

I hope this helps as a guide. If your coating falls into these categories then please confirm this with the EPA.

Best wishes,

Ron Joseph