Paints & Coatings Resource Center

Ask the Expert Question-and-Answer Archive

by Ron Joseph

October, 2004

Definition of VOC and HAP

Q. In the U.S if Ethylene Glycol and Propylene Glycol are used in a latex paint formula are these considered to be VOCs?

The definition of VOC is " ... any organic compound that participates in a photochemical reaction, except those that have negligible photochemical reactivity. ..." In other words, ANY organic compound that evaporates into the air is, by default a VOC unless it is listed by the EPA as Exempt Compound. Acetone, PCBTF, Methyl Acetate, Methylene Chloride and Volatile Methyl Siloxanes are the solvents most commonly used in painting operations, that are exempt. Since Ethylene Glycol and Propylene Glycol are volatile compounds and are not listed as exempt, they are, by default VOCs.

EPA Method 24 provides a list of ASTM methods that are used to determine VOCs experimentally. ASTM D2369 is the definitive test for experimentally determining VOC status. If either of the two solvents you mentioned evaporate, or even partially when subjected to 230oF (110oC) for one hour, then they are VOCs.

Please note that some glycol ethers are listed by EPA as Hazardous Air Pollutants (HAP). The definition of HAPs is given in Sections 112(b)(2) and (3). The original list of 189 HAPs (now reduced to 188 compounds) can be found at

I hope this helps you.

Best wishes,

Ron Joseph

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