In a move welcomed by marketers looking to sell diesel exhaust fluid (DEF) at truck stops, EPA officials say the additive will not be governed by underground tank storage rules. The agency’s Office of Underground Storage Tanks said in a Sept. 22 memo to regional program managers that DEF does not meet the definition of a hazardous substance because it contains less than 2% and thus falls under the UST program's de minimus exemption, says the National Assn. of Truck Stop Operators.
DEF is a 32.5% aqueous solution of urea used in Selective Catalytic Reduction technology as a way to reduce nitrogen oxide emissions from heavy-duty diesel engines, a requirement under EPA's 2007 Heavy-Duty Highway Rule. DEF solution may contain a small amount of ammonia, which is the only component that could be considered hazardous. The international standard for DEF allows no more than 0.2% by weight of alkalinity, measured as ammonia. DEF manufacturers say any amount of ammonia in DEF is considered a contaminant, according to NATSO. Manufacturers say ammonia should be less than 0.2%.
--Carole Donoghue, cdonoghue@opisnet.com