On April 15, 1998, the United States Environmental Protection Agency (EPA) announced its conclusion regarding the technology basis for Best Available Technology (BAT) options as part of its pulp and paper Cluster Rule.
The combined air and water Cluster Rule for the pulp and paper industry protects human health and the environment by reducing toxic pollutant releases to the air and water. It sets effluent limitations and pretreatment guidelines for all bleached pulp, paper, and paperboard mills.
In general, the Cluster Rule requires that pulp bleaching processes switch from those using elemental chlorine (Cl2) to those using oxidants and specialized extraction sequences, which produce minimal or no adsorbable organic halide (AOX) compounds.