The Accelerated Reduction/Elimination of Toxins (ARET) Challenge was a voluntary program initiated in 1994 by the Government of Canada. Unlike the U.S. 33/50 Program, ARET involved industry partners in negotiation and cosponsorship of the program, with the intention that early involvement would yield stronger commitment to voluntary reductions. We review the program's self-reported success in delivering emissions reductions. For 17 ARET substances that were also covered by Canada's National Pollutant Release Inventory, we employ treatment effects regressions to control for self-selection bias. We find evidence that ARET accelerated emission reductions in five cases, slowed reductions in two cases, and had no discernible effect in ten cases. Industry cosponsorship apparently did not have the intended effect and instead resulted in program features such as data confidentiality that significantly undermined the program's credibility. (Contains 4 tables and 5 footnotes.) [A 12-page Appendix containing additional results and methodological details, along with 2 figures, 7 tables, and 2 references, is available through this publisher's Web site at http://www3.interscience.wiley.com/cgi-bin/ jhome/34787.]