The chart to the right is a screen grab taken directly from the EPA's own TRI website (Toxics Release Inventory) ranking the largest Dioxin polluters in Texas in 2009. The emission numbers don't look all that big but that's deceiving because Dioxin is the Black Mamba of industrial poisons. It's so toxic, it's measured in grams and not pounds or tons. It's a carcinogen, wreaks havoc with hormones and immune systems in adults, children and fetuses, and has a variety of other nasty human health impacts. There is no "safe" threshold level of exposure to Dioxin. It's what made Agent Orange so toxic. It's why Love Canal, New York and Times Beach, Missouri are federal Superfund sites. Dioxin is associated with hazardous waste incinerators, large chemical plants and paper mills because it's formed when chlorine is heated or burned. Now, knowing all that, maybe you'd think the cement plants in Midlothian would be the largest local source of the stuff. But no. Look at #9 on EPA's list. It's Exide's lead smelter in Frisco. Look at the company it's keeping.  Chemical plants, power plants, pulp mills and refineries. There's only one other North Texas plant in the top 22 (out of 74 total Dioxin polluters in Texas) and that's an aluminum smelter in Commerce. In 2009, the Frisco smelter released more Dioxin than any cement plant in Texas. More than the Valero Refinery in Corpus Christi, or the ExxonMobil Refinery in Beaumont. More than the Martin Lake coal-fired power plant. In 2009, Exide was Collin County's only source of industrial Dioxin. There were no facilities in Denton, Dallas or Tarrant Counties emitting Dioxin. And this high ranking was based on Exide's claim that most of the Dioxin that the smelter created onsite went "poof" after being treated, and left only 2 of 13 grams behind. If the company is fudging only a little bit, it means the smelter could in fact be in the top five for that year. What's remarkable is that all of the other polluters at the top of that list are much, much bigger operations than Exide's doublewide-looking smelter in Frisco. When it comes to the most toxic substance ever tested by EPA, Exide is the little smelter that belched. It produces Dioxin numbers all out of proportion with it size. Since reporting for Dioxin began in 2000, Exide's Frisco smelter has estimated producing over 94 grams, and releasing over 18. That latter amount alone is enough to give every resident of Frisco cancer several times over. But unlike heavier stuff coming out of the stacks at Exide, Dioxin can travel far, far downwind. Way past the smelter's puny "non-attainment" zone.  Way past the Frisco city limits. So next time you see some news about those citizens trying to relocate that old smelter, maybe you won't consider their efforts so provincial, and instead write them a check for helping you reduce your average daily intake of poison.