A tanker truck hauling sodium bisulfate leaked about 200 gallons of the chemical Tuesday morning onto Interstate 94 east of downtown St. Paul. Three people were taken to Regions Hospital with respiratory problems. A St. Paul district fire chief, Stan Jadwinski, tells WCCO Radio news some of the chemical made its way into the Mississippi River but the environmental impact is believed to be minimal. Booms were set up on the river to collect the chemical which is used in swimming pools. Traffic was interrupted for several hours.