Ferric ferrocyanide could be treated as a toxic pollutant

Under a court order, the US Environmental Protection Agency (EPA) is investigating whether ferric ferrocyanide is a pollutant that should be regulated under the Clean Water Act.

A recent court case involving an electric company raised the issue of whether ferric ferrocyanide is part of the ‘cyanides’ group of regulated compounds. The court remanded the issue to the EPA for an administrative determination, and a 10 June deadline to issue a ruling on the substance, which is used as pigment in printing inks and paints, has now been extended to 10 July, making this a five-and-a-half-months comment period, according to an announcement in the Federal Register. Ferric ferrocyanide is also used as pigment in some resin enamels, linoleum, leather cloth, carbon papers, typewriter ribbons, rubbers, plastics, artists’ colours and in the removal of hydrogen sulphide from gases.

Once the determination is final, facilities would need to treat ferric ferrocyanide as a toxic pollutant, consider the compound to be a hazardous substance under the Comprehensive Environmental Response, Compensation and Liability Act release reporting provisions and quantify releases of this compound as part of the cyanides group for Toxic Release Inventory reporting under the Emergency Planning and Community Right-to-Know Act.

Ferric ferrocyanide is a compound that usually contains some water and some alkali ferrocyanide. It is in the form of a dark-blue powder or lumps that it loses all of its water at 250 degrees Fahrenheit with partial decomposition. It is practically insoluble in water, diluted acids and most organic solvents.

Comments should be submitted to Ferric Ferrocyanide Preliminary Administrative Determination, US EPA, Engineering and Analysis Division, Office of Science and Technology, Ariel Rios Building, 1200 Pennsylvania Ave. NW, Washington, DC 20460.

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