Corpus Christi Ecological Services Field Office contaminants staff recently participated in a U.S. /Mexico bi-national oil spill response exercise in Matamoros, Tamaulipas, Mexico.  The exercise, called MEXUS Arietes 2006 was the fourth joint exercise since the signing of an agreement of cooperation between the U.S. and Mexico regarding pollution of the marine environment by discharges of hydrocarbons and other hazardous substances.  This year’s exercise was sponsored by Petroleos Mexicanos (PEMEX) in partnership with the U.S. Coast Guard and Mexican Navy.  PEMEX is the sole supplier of all gasoline in Mexico.  The 2006 MEXUS Gulf exercise addressed trans-boundary, socio-economic and logistical issues of such a pollution incident and examined established response procedures and implementation solutions from previous spill drill exercises.  Service personnel provided technical assistance in the operations and planning section relating to the minimization and rehabilitation of oil wildlife and habitat.  Participating agencies included:  U.S. Department of Homeland Security, U.S. Coast Guard, U.S. Customs and Border Protection, U. S. Department of Interior, U.S. Environmental Protection Agency, U.S. Department of Commerce, U.S. Department of State, Texas General Land Office, Armada of Mexico, PEMEX and 15 other federal, state, and local agencies from both countries.