Texas is No. 1 — in mercury

Per the Environmental Integrity Project, Texas power plants are collectively No. 1 in the nation in mercury emissions.

And, worse, they're individually No. 1 — and Nos. 3-5, too:
1. Luminant Generation, Martin Lake Steam Electric Station & Lignite Mine in Rusk County, TX (1,501 lbs. of mercury emissions);
2. Southern Co., Gaston Steam Plant in Shelby, AL (1,244 lbs. of mercury emissions);
3. Luminant Generation, Big Brown Steam Electric Station & Lignite Mine in Freestone County, TX (1,240 lbs. of mercury emissions);
4. Luminant Generation, Monticello Steam Electric Station & Lignite Mine in Titus County, TX (911 lbs. of mercury emissions);
5. Luminant Generation, Sandow Steam Electric Station in Milam County, TX (841 lbs. of mercury emissions).

You'll also note another common factor — Luminant, the former generating arm of TXU.

Full report (PDF) is here.