Houston cleaning up pollution by going after ethane cracker emissions
Scientists have learned that flaring of excess gasses at petrochemical plants and refineries, like this one along the Houston Ship Channel, can be key contributors to ozone pollution.
Reid R. Frazier/The Allegheny Front
Refineries and petrochemical plants line the Houston Ship Channel, a 26-mile industrial canal. Houston has never met federal air quality standards for ozone.
Reid R. Frazier / The Allegheny Front
HOUSTON – The largest chemical hub in the Americas courses through this city in a seemingly unending line of plants that produce about a quarter of the country’s petrochemicals.
These plants have helped fuel the city’s economic rise. But they also have added to its poor air quality, with emissions that have been linked to asthma, cancer and heart attack.
In recent years, Houston has found ways to reduce air pollution, in part by zeroing in on chemical plant emissions. Experts say Houston’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. The plant would take ethane from the Marcellus shale and convert it into ethylene – a key building block for plastics and chemicals – through the “cracking” process.
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 an oxidant that can burn lung tissue, aggravate asthma and increase susceptibility to respiratory illnesses like pneumonia and bronchitis, according to the agency.
Ozone is formed when volatile organic compounds mix with other forms of pollution in the presence of sunlight. Environmental scientists say the biggest impact a cracker plant would have in Pittsburgh would be through releases of VOCs.
The company has said 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. The company has used Shell’s Norco plant in Louisiana in the past as a reference when it proposed its Pennsylvania cracker. Norco produces roughly twice the VOCs of U.S. Steel’s Clairton Coke works, currently the highest emitter in Southwestern Pennsylvania, according to the EPA.
Shell spokeswoman Kimberly Windon said the company did 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,” she said. “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 Deer Park, Texas, refinery and ethylene plant 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, said the biggest pollution problem posed by a cracker would be emissions of VOCs and nitrogen oxides.
Osborne said the plant would likely be a major source of new pollution, with more than 50 tons per year of VOCs and 100 tons of nitrogen oxides, though he has yet to see any estimates from the company.
“I expect it will be a large source of ozone precursors, and this would be located in an area that’s already failing to meet federal health-based standards for ozone,” he said.
Houston may hold clues to how a cracker, which is expected to bring in 10,000 short-term construction jobs, and up to 17,000 indirect jobs to the region, 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, a vast complex of pipes, distillation towers and storage tanks.
Houston’s air has long borne the brunt of its industrial output. It has never met federal air quality standards for ozone. An array of studies has shown pollution’s negative impact. One study linked high ozone incidents to increased rates of cardiac arrest in Houston; others have found associations between high rates of asthma and childhood leukemia in neighborhoods near the chemical industry’s base along the Houston Ship Channel.
But in the last decade, Houston’s air has improved, in part because regulators have targeted the petrochemical industry.
The city’s air quality nadir was in 1999.
“We were the capital of ozone,” says Elizabeth Hendler, a former state regulator who now works as an environmental consultant to industry.
In that year, Houston surpassed Los Angeles as having the highest ozone levels in America.
“That was kind of a wake-up call,” Hendler said.
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 a few years.
The state undertook a wide-ranging series of studies. Aircraft from NASA and the National Oceanic and Atmospheric Administration flew over the ship channel with special emissions-sensing equipment.
They found big leaks. 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,” said Harvey Jeffries, a retired University of North Carolina chemist who studied Houston’s air and advised business and research groups on Houston’s air problems.
Ethylene and propylene – the two main products made in a cracker – 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 said.
When they looked at Houston’s industrial corridor, scientists realized chemical plants had been chronically underreporting their emissions. A lot of this pollution was “fugitive” emissions – leaks from valves, flanges, tiny holes in pipes and incomplete combustion of waste gasses in the plants’ flares.
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, and implemented a cap-and-trade program for Houston’s petrochemical plants.
What effect did all this have?
“Well, ozone went down – a lot,” Hendler said.
The Texas Commission on Environmental Quality estimates the city’s ozone levels have decreased about 20 percent since 2001.
The number of days when the air in Houston exceeds the EPA’s current eight-hour average for ozone of 75 parts per billion 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.
In spite of recent strides, Houston still has never met any federal guidelines for ozone.
The city will also 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,” said Larry Soward, a former regulator for the Texas commission 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 have to either reduce pollution at one of their own facilities, or buy credits from a company that’s reduced them at theirs. They will also have to use tighter pollution controls.
Still, Soward thinks they could go even further by implementing more fence-line monitoring and increasing maximum fines on plants, now $25,000 a day.
“We just don’t do that in Texas,” he said.
The industry contends that current monitoring and regulations are working. ExxonMobil, for example, reduced its emissions by 50 percent in the past decade. And industry backers say Houston’s chemical sector has been a 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,” said Craig Beskid, executive director of the East Harris County Manufacturers Association, an industry group in Houston.
Beskid said Houston’s chemical and refinery sector contributes about 30,000 jobs with salaries ranging from $40,000 to $200,000 a year. That economic engine contributes to a better quality of life, he said.
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 said. “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 said, the monitors have been good for the city’s air, and good for the companies’ bottom lines.
Reid Frazier is a reporter with The Allegheny Front, a radio program covering the environment in Pennsylvania. Find more stories at alleghenyfront.org. This work was funded in part by the Fund for Investigative Journalism. Next Week: Plants provide work, but it can be deadly.