EXPOSÉ | "The Scientific Method"| PBS

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Watch this preview of "The Scientific Method" Exposé: America's Investigative Reports, on PBS.

Black smoke from an oil refinery darkens the skies over Houston - airspace already ranked among the most polluted in the country. For thousands of residents living right alongside the city's industrial plants, the odors and dust in the air are clear signs the plants are polluting the environment. But no one has ever bothered to tell them exactly what they are breathing...until now. EXPOSÉ details the Houston Chronicle investigation that gave a city the answers to some troubling environmental questions.

And watch the full episode when it premieres online, Wednesday, July 18, at 12 noon ET. (Or check your local listings for broadcast dates on PBS nationwide, beginning Friday, July 20.)

For web-exclusive video and audio features, and to stream other episodes in the series, go to <a class="link" rel="nofollow" href="http://www.pbs.org/expose">http://www.pbs.org/expose</a>