Erin Brockovich isn’t one to let an environmental calamity get overlooked on her watch. The activist is now investigating why a high number of teenagers living in Le Roy, N.Y., seem to be exhibiting facial tics and verbal outbursts now that there is new evidence a toxic chemical spill wreaked havoc on the water more than four decades ago. Brockovich, who gained fame after a movie immortalized her fight against a power company in California, was asked by local parents to look into the issue. Forty years ago, a train derailed near the town, spilling cyanide and an industrial solvent. Local officials say that environmental studies have not shown a link between neurological issues and the disaster.