Indulin AA-86 is a fatty amine derivative used as an asphalt emulsifier, and manufactured by WestRock’s Ingevity division. As a proprietary formulation, not much has to be disclosed to the public about exactly what is in it, but knowing that it is a fatty amine derivative, allows us to make some assumptions:
- It is not particularly water soluble on its own as a concentrate.
- It contains Ethyl Acrylate (an ester of acrylic acid) which is used in polymerization. This is a reactive monomer.
- It is an emulsifier, so in certain cases will bond to aromatic organics, or anything with a benzine ring.
- When mixed with hydrochloric acid and water, it is significantly more water-soluble.
Indulin AA-86 made national news after as many as 24 gallons of the compound, possibly in a mixture with hydrochloric acid were reported to have been backfed into the Corpus Christi, TX city water supply at some point in December 2016. The backfeed originated from a plant leased to Ergon Asphalt and Emulsions on property adjacent to one of the two Valero refineries in the city’s large refinery complex.
This led to a temporary drinking water ban issued on December 14, 2016 throughout the city of 320,000 residents. The ban remained in place in 85% of the city for more than two days, leading to school closures and emergency deliveries of bottled water, after which restrictions were tailored on December 17 to smaller portions of the city.
City officials posted a warning to residents that “Boiling, freezing, filtering, adding chlorine or other disinfectants or letting the water stand will not make the water safe“.
It was reported December 17 that city officials were investigating four cases of skin and intestinal issues that were consistent with possible symptoms of exposure, but these claims were dismissed by Mayor Dan McQueen as “rumors”, and twelve “reports of possibly related symptoms from prohibited water use” were described as “unconfirmed” by the EPA. The ban was lifted December 18 after 28 samples of city water failed to find Indulin AA-86 contamination.
Many people are still concerned that Indulin AA-86 might be in the water of Corpus Christi, or in other city supplies. While there certainly is always a possibility of unintentional backflows occurring in any city at any time, one needs to understand that in the event of backflow, the net area effected is usually very small and typically highly diluted.
In attempting to address waterborne contaminants like Indulin AA-86, it is important to understand that no verified 3rd-party protocol currently exists to validate a filter’s removal/reduction of Indulin AA-86 from drinking water, and most likely never will. There are hundreds of thousands of proprietary compounds in use in the marketplace, and we can’t test filtration systems for removal of everything. In the Corpus Christi incident, a highly dilute solution of INdulin AA-86 along with hydrochloric acid was backfed into the city where it was diluted further by existing water, and where it reacted further with reactive compounds in the water, such as hydrocarbons. This makes for complex chemistry, and why I advocate for whole-house (POE) and Point-of-Use (POU) filtration wherever possible to minimize the risk when situations like this occur.
When people ask me for my best advice on addressing water that may be contaminated with minute amounts of Indulin AA-86, my advice is that carbon block filtration followed by ultrafiltration is the bare minimum for beginning to address the presence of a dilute fatty amine, and that I’d want to follow that with filtration by Reverse Osmosis to minimize the risk.