The Texas Commission for Environmental Quality has designed an unprecedented, market-based emissions reduction program to trade four highly reactive VOCs (HRVOCs) in the Houston/Galveston/Brazoria (HGB) area, one of the most polluted regions in the country. These compounds, ethylene, propylene, the isomers of butene, and 1,3- butadiene, can form ozone very rapidly and lead to Transient High Ozone Events that have dominated the Ozone Design Values in the HGB area for more than two decades. The EPA proposed approval of the HRVOC Emissions Cap and Trade program in 2005 as a means to help meet the one-hour ozone standard of 0.12 ppm. Under the current eight-hour ozone attainment standard of 0.08 ppm, concerns have surfaced regarding the program's effectiveness in helping to achieve said standard by the 2010 deadline. Several policy implications of this uniquely complex program are examined against four other emissions trading programs and against uncertainties within the program itself.