The largest chemical hub in the Americas courses through this city in a seemingly unending line of plants. They produce about a quarter of the country’s petrochemicals and are a big reason for Houston’s economic rise. But they also have added to its poor air quality, with emissions that have been linked to asthma, cancer and heart attacks.

In recent years, Houston has found ways to reduce air pollution—in part, by zeroing in on chemical plant emissions. Experts say the city’s experience may show others how to keep chemical emissions down, even as the industry expands along the Gulf Coast—and possibly into Pennsylvania.

From Pennsylvania to Texas, the chemical industry is building new plants to take advantage of vast deposits of natural gas opened up by the fracking boom. Shell Chemical is eyeing building an ethane cracker in Monaca in Beaver County, Pennsylvania. The plant would take ethane from the Marcellus Shale and convert it into ethylene—a key building block for plastics and chemicals—through a process known as “cracking.”

LISTEN: “What Pennsylvania Can Learn from Houston’s Approach to Air Pollution”

Shell’s Pennsylvania cracker would be northwest of Pittsburgh in a region that already fails federal air quality standards for ozone and other pollutants, according to the Environmental Protection Agency. Ozone is a pollutant that can burn lung tissue, aggravate asthma and increase susceptibility to respiratory illnesses like pneumonia and bronchitis.

Ozone is formed when volatile organic compounds (VOCs) mix with other forms of pollution in the presence of sunlight. Air quality experts say the biggest impact a cracker plant would have in Pittsburgh would be through releases of VOCs.

The company says differences in local permitting rules and the type of raw materials it would use make it hard to project what kinds of emissions a Pennsylvania cracker would produce. In the past, the company has used its Norco plant in Louisiana as a reference when it proposed the Pennsylvania cracker. Norco produces roughly twice the VOCs of U.S. Steel’s Clairton Coke works—currently the highest emitter in southwestern Pennsylvania.

Shell spokeswoman Kimberly Windon says the company does not have specifics about what types of emissions the plant would produce—or what types of permitting it would need.

“I can tell you that if this project does move forward, we will design, build and operate the facility to ensure compliance with all state, federal and local air quality standards,” Windon says. “Environmental health is important to us. We’re definitely committed to environmental responsibility in the communities where we operate.”

Shell recently agreed to spend $115 million to clean up emissions at its refinery and ethylene plant in Deer Park, Texas after the Department of Justice filed a complaint alleging the plant’s flares were emitting improper amounts of VOCs and cancer­-causing pollutants.

Joe Osborne of the Group Against Smog and Pollution, an environmental advocacy group in Pittsburgh, says the Beaver County plant would likely be a major source of new pollution. Annually, the region could see 50 tons of VOCs and 100 tons of nitrogen oxides—another key component of ozone—though he has yet to see any estimates from the company.

“I expect it will be a large source of ozone precursors,” Osborne says. “And this would be located in an area that’s already failing to meet federal health-­based standards for ozone.”

Looking to Houston

Houston may hold clues for how a cracker would impact air quality. At the heart of the industry’s production chain is the Houston Ship Channel, a 26-­mile canal lined with refineries and chemical plants. It’s a hulking complex of pipes, distillation towers and storage tanks.

Houston’s air has long borne the brunt of the ship canal’s industrial output. The city has never met federal air quality standards for ozone, and an array of studies have shown pollution’s negative impact on residents.

One study linked high ozone incidents to increased instances of cardiac arrest in Houston. Others have found high rates of asthma and childhood leukemia in neighborhoods near chemical plants.

The fact that Houston has no zoning laws adds another layer of complexity to the issue. Because of this, some residents live right across the street from huge refineries and chemical plants. Apollonia Martinez lives in Manchester, a low-income neighborhood between a rubber plant and a refinery. She says one of her sons has been having a lot of asthma attacks.

“Every now and then, I have to give him treatments because of his breathing problems at night,” Martinez says. Martinez would like to leave, but she can’t afford rents in more expensive neighborhoods.

In the past decade, however, Houston’s air has improved—in part because regulators have targeted the petrochemical industry.

“We were the capital of ozone,” says Elizabeth Hendler, a former state regulator who now works as an environmental consultant to industry. In 1999, the city’s air quality nadir, Houston surpassed Los Angeles as having the highest ozone levels in America. “That was kind of a wake­-up call,” Hendler says.

Not long afterward, in 2003, Toyota decided against locating a plant in the region because of the city’s air. Hendler says the number of air monitors in Houston doubled in just a few years. And the state undertook a wide-­ranging series of studies.

Along the Houston Ship Channel-2

The 26-mile Houston Ship Channel is a dense network of refineries and petrochemical plants. Houston has never met federal air quality standards for ozone. Photo: Reid Frazier

Aircraft from NASA and the National Oceanic and Atmospheric Administration even flew over the ship channel with special emissions-­sensing equipment. They found big leaks at the plants. The worst were from chemical plants with crackers that made ethylene and propylene—two basic building blocks of plastic.

“The plants were having 1,000-pound releases, 5,000-pound releases, 20,000-pound releases—in one case, 200,000-pound releases,” says Harvey Jeffries, a retired University of North Carolina chemist who has studied Houston’s air and advised business and research groups on Houston’s air problems.

Ethylene and propylene are considered “highly reactive” VOCs, meaning they can create large plumes of ozone in a matter of hours under the right conditions.

“When that stuff gets emitted in the daytime, it cooks up the highest amount of ozone you’ve ever seen,” Jeffries says.

When they looked at Houston’s industrial corridor, scientists realized chemical plants had been chronically under­-reporting their emissions. A lot of this pollution consisted of so-called “fugitive” emissions—leaks from valves, flanges, tiny holes in pipes and incomplete combustion of waste gasses.

To get the city’s air under federal air pollution limits, Texas implemented a suite of environmental reforms. The state created special limits on emissions of highly reactive VOCs like propylene and ethylene. They also implemented a cap­-and-­trade program for Houston’s petrochemical plants.

The results were pretty striking.

“Ozone went down—­­a lot,” Hendler says.

The Texas Commission on Environmental Quality estimates the city’s ozone levels have decreased about 20 percent since 2001.  And the number of days when the air in Houston exceeded the EPA’s current eight-hour average standard for ozone went from around 100 a year in 2005 to under 35 days in 2012. Emissions of other pollutants, including carcinogenic chemicals released in petrochemical manufacturing, also decreased.

Progress, But No Cure

In spite of recent improvements, Houston still struggles with air quality. The city will see huge expansions of its petrochemical sector in the next few years thanks to the fracking boom. Several new or expanded ethane crackers are slated to go online to take advantage of cheap natural gas. This has some clean air advocates worried.

“We’ve made significant progress,” says Larry Soward, a former regulator for the Texas Commission on Environmental Quality and president of Air Alliance Houston. “But let’s not pat ourselves on the back too much. So far, we have not met a single [federal] standard for ozone, ­­and we’re talking about adding all these new pollution sources.”

Companies looking to expand in Houston will either have to reduce pollution at one of their own facilities, or buy credits from a company that has reduced pollutants at theirs. New facilities will also have to use tighter pollution controls.

Still, Soward thinks the city could go even further—by implementing more fence-­line monitoring and increasing maximum fines on plants, which are now $25,000 per day.

“We just don’t do that in Texas,” he says.

The number of days when the air in Houston exceeded the EPA’s current eight-hour average standard for ozone went from around 100 days a year in 2005 to under 35 days in 2012. Emissions of other pollutants, including carcinogenic chemicals released in petrochemical manufacturing, have also decreased.

The industry contends that current monitoring and regulations are working. Many plants are using infrared cameras to detect leaks. ExxonMobil, for example, says it has reduced emissions by 50 percent at its sprawling Baytown facility in the past decade. And industry backers say Houston’s chemical sector has been key to helping the city’s economy avoid the worst of the recession.

“A great benefit in anyone’s life is to have a good job,” says Craig Beskid, executive director of the East Harris County Manufacturers Association, an industry group in Houston.

Beskid says Houston’s chemical and refinery sector contributes about 30,000 jobs, with annual salaries ranging from $40,000 to $200,00. He says that economic engine contributes to a better quality of life.

Steve Smith, technical advisor to the industry­-funded Houston Regional Monitoring Network, which operates around a dozen air pollution monitoring stations around the city, says the key to keeping emissions low is simple: Keep an eye on it.

“If you monitor, it will get better,” he says. “That’s exactly what happened here.”

Smith’s group tests for more than 150 pollutants to help oil, gas and petrochemical businesses meet federal air quality mandates.

“We set up a network early on, where if we saw a value too high, we sent out a notice to the companies saying, ‘Look at what’s happening. See if you have something that’s going on.’”

It helped companies cut down on leaks at their facilities. In that way, he says, the monitors have been good for the city’s air—and good for the companies’ bottom lines.

###

This story is part of our series “The Coming Chemical Boom,” which is funded in part by the Fund for Investigative Journalism.