Houston is “the third-most toxic city in the United States of America.”

Houston businessman Farouk Shami, running for governor, turned to his leading Democratic foe on Monday night and leveled a foul charge.

In a televised debate, Shami told Bill White, the former Houston mayor: “Our city is the third-most toxic city in the United States of America.”

White didn’t take issue with Shami’s description, but it was news to us. We decided to check into the Bayou City’s “ick” ranking.

Shami’s campaign said the candidate based his statement on a 2009 article in Forbes magazine putting Houston behind only Atlanta and Detroit for toxicity among major U.S. cities.

The magazine said it based its rankings of the nation’s 40 largest metropolitan statistical areas on data provided by the U.S. Environmental Protection Agency.

“We counted the number of facilities that reported releasing toxins into the environment,” the magazine said, “the total pounds of certain toxic chemicals released into the air, water and earth, the days per year that air pollution was above healthy levels, and the number of times the EPA has responded to reports of a potentially hazardous environmental incident or site in each metro area’s principal city.”

Its article states Houston’s residents live with with air that’s far filthier than it should be.

“Facilities in Houston released 88.7 million pounds of toxic chemicals in the environment in 2007,” the magazine says, “and the former site of a methanol fire and chemical explosion number among the city’s 50 sites necessitating an EPA response. Factories that serve the local petrochemical industry emit benzene and 1-3 butabeine, toxins proven to be particularly harmful, that the area’s intense sunlight and lack of wind keep trapped in the local area’s atmosphere.”

Jim Lester, vice president of the Houston Advanced Research Center, a Woodlands-based nonprofit group that studies and promotes sustainable development, is quoted saying Houston has become “one of the favorite places in the world for doing air-quality science.” He saw that as a boon: “The more people understand about it (air quality), the more changes are likely that will take us in a positive direction.”

When we reached Lester, he revisited pollution levels reported by industries and posted online by the EPA. In 2007, Harris County industries reported either releasing or disposing of 36.1 million pounds of toxic chemicals, while industries around Detroit in Wayne County nearly matched that dubious achievement, reporting the disposal or release of nearly 30 million pounds of toxic pollutants.

Shami correctly referred to a recent national comparison. We rate his statement as True.