In 2011, EPA’s Environmental Fate and Effects Division (EFED) in the Office of Pesticide Programs and Canada’s Pesticide Management Regulatory Authority (PMRA) formalized the NAFTA degradation kinetics project.

If you are reviewing or reproducing results initially obtained before this guidance was issued in March 2015, see Standard Operating Procedure (Superseded) for Using the NAFTA Guidance to Calculate Representative Half-life Values and Characterizing Pesticide Degradation. Search EPA Archive

• Standard Operating Procedure for Using the NAFTA Guidance to Calculate Representative Half-life Values and Characterizing Pesticide Degradation, Version 2 (PDF)(29 pp, 480 K, March 23, 2015 )
  This document provides the results of the degradation kinetics project and describes a general approach for calculating and selecting representative half-life values from soil and aquatic transformation studies for risk assessment and exposure modeling purposes.