A new report shows area phosphate plants adversely affect southeastern Idaho's air quality and possibly contribute to serious health hazards. The tribes joined Chubbuck and Pocatello in requesting the study from the Agency for Toxic Substances and Disease Registry in the Health and Human Services Department. It found overall levels of particulate matter dropped more than 30 percent since 1994 but that J.R. Simplot Co. and FMC Corp. released large quantities of toxic chemicals into the air. "Overall, we were happy with what they put in the study,'' tribal air quality manager Farshid Farsi said. Farsi said people living downwind from the plants are affected and the tribes want more research into other health effects. Residents in the region express concerns about asthma, upper respiratory illness and heart disease. The report found all are consistent with research produced by FMC and Simplot. But, the study said, those illnesses could be attributed to smoking and exposure to indoor contaminants. An FMC spokesman maintained air emissions improvements in progress will reduce the plant's small particle emissions by 80 percent in two years. A Simplot spokesman questioned some study methods and conclusions but agreed "we all have to be very vigilant about air quality."