The threat of exposure to noxious chemicals - in the air, the land or the water - is nothing new in Louisiana. The state has ranked No. 2 in toxic emissions, behind Texas, just about every year since 1988, when the EPA began requiring industry to tally its pollution. That year, the first in which the EPA's Toxics Release Inventory was published, Louisiana's petrochemical plants acknowledged releasing nearly 1 billion pounds of hazardous wastes at their plant sites, or about 238 pounds for every person then in Louisiana.