Reading Time: 7 minutes

HOUSTON, May 31, 2002 — In a discovery with national implications, a group of government, academic and private researchers involved in a $20 million study of Houston’s air quality have found that operators of petrochemical plants in the city’s vast industrial complex have been significantly underestimating emissions of key air pollutants in required reports to regulators.

Smog-forming and toxic gases were “consistently” measured at levels three to 10 times greater — and in some cases, “100 or more [times] greater” — than local oil refineries and chemical plants reported releasing, according to a recent analysis of the Houston findings by federal, state and academic experts.

The findings suggest that the current smog reduction plan for the city, signed by then-Governor George W. Bush, might not be enough to solve Houston’s chronic smog problem. And, coupled with similar findings in an earlier study in Philadelphia, the Houston readings are raising questions about whether petrochemical facilities nationwide, such as oil refineries and chemical manufacturing plants, are underestimating the real volumes of air pollution they release.

“My suspicion is that this is true of similar kinds of industries across the country,” Peter Daum, a leading researcher involved in both the Houston and Philadelphia studies, told the Center for Public Integrity.

Daum and other experts familiar with the Houston research speculate that company officials are submitting low estimates because the Environmental Protection Agency’s authorized methods for calculating emissions don’t reflect actual operating conditions in highly complex petrochemical plants.

“I would hope that the EPA would revisit the issue” of how accurate these pollution-estimating tools are, said Daum, a chemist who heads the atmospheric sciences division of the Department of Energy’s Brookhaven National Laboratory. “I personally think it’s a problem.”

The Houston and Philadelphia findings relate to two interconnected air quality issues that affect numerous metropolitan areas — ground-level ozone and airborne toxic pollution — and the often-contentious policy debates over how to address them.

The researchers’ discoveries involve a broad family of dozens of chemicals known as volatile organic compounds, or VOCs. As gases, these chemicals contribute to atmospheric reactions that produce ozone, a major respiratory hazard. Many VOCs also pose health-related concerns by themselves, because they have cancer-causing or other toxic qualities.

Petrochemical plants are hardly the only source of VOCs. They are also emitted in collectively huge volumes by the nation’s millions of vehicles and by many other industrial facilities as well.

Still, Frank O’Donnell, executive director of the Washington-based Clean Air Trust, said the findings indicating emission underestimates by petrochemical plants in two cities “may help explain why there are so many ozone problems around the country.”

There are 142 active refineries in 31 states, according to the Oil & Gas Journal in a December 2001 issue. The locations include metropolitan areas that the EPA ranks as having some of the nation’s worst ozone problems, including Los Angeles, Houston, New York, Chicago and Philadelphia.

Airborne toxins a national problem

Earlier this month, the American Lung Association reported that more than 142 million Americans live in areas where “unhealthy” levels of ozone are measured, three decades after the first Clean Air Act became law. The estimate was for the 1998-2000 period, the latest with complete monitoring data.

This week, the association joined other major environmental and health groups in announcing they would pursue litigation to get the EPA to stop what they alleged was “foot-dragging” in its implementation of a tighter national ozone standard adopted during the Clinton administration.

Airborne toxic pollution also remains a thorny national issue. In April, the Knight Ridder news service reported that an unreleased EPA study had calculated that toxic chemicals in the air pose a cancer risk to the U.S. population that is 10 times the level the agency deems acceptable. Such chemicals, which come mainly from vehicles and industry, result in 150 new cancer cases per year, the study estimated.

One of the pollutants now drawing closer attention from environmental regulators because of the Houston study — butadiene — illustrates how the ozone and toxic pollution issues overlap.

A potent ozone-forming pollutant, butadiene is also listed on an authoritative California registry as a recognized carcinogen. In 2000, the last year for which official data are available, 191 industrial plants in 34 states reported releasing nearly 2.23 million pounds of the chemical to the environment. More than 97 percent of that total – about 2.17 million pounds – was discharged to the air, according to statistics released this month by the EPA.

Because of the new findings about VOCs in the Houston area—home to the nation’s largest concentration of refineries and chemical plants—state officials are preparing major revisions to their sweeping smog-reduction plan for that city. These changes will be presented to the three commissioners who oversee the state’s pollution control agency, the Texas Natural Resource Conservation Commission, next week.

President Bush submitted the current Houston smog plan for EPA approval in one of his last official acts as governor, after asserting in his presidential campaign that it would be extremely tough on local industries. Criticizing Bush’s record, environmentalists and Democratic presidential nominee Al Gore had cited Houston’s poor air quality – especially its replacement of Los Angeles as the city with the nation’s worst ozone problem.

Flaws in Houston’s smog plan

It is widely acknowledged that the Houston plan’s demand for a 90 percent cut in industrial pollution is one of the most stringent mandates ever imposed at one time, if not the strictest. It does not apply to VOCs, however, but to nitrogen oxide, a combustion byproduct that also forms ozone. That represented a change from previous regulatory efforts.

Beginning in the early 1970s, federal and state ozone-reduction policies had focused on controlling VOC emissions in Houston. But in the late 1990s, new computer modeling projected dramatic cuts were needed in nitrogen oxide for the city to comply with the national ozone standard. The deadline for complying with that standard is 2007. State officials designed the new plan to reflect that projection, and Bush signed it in December 2000. After he became president in 2001, the EPA approved the plan.

Its premises are now being reconsidered, however, because of the new VOC findings. They came from a $20 million study, involving scientists and engineers from more than 40 government, academic and private institutions. The study made extensive measurements of ozone and ozone-forming emissions in the Houston area and other locations in East Texas, both on the ground and from aircraft. Researchers collected the data in 2000 and have been analyzing them since that time. [See study results.]

Jeff Saitas, executive director of the Texas environmental commission’s staff, told the Center that this analysis indicates Houston-area industries emit significantly greater volumes of VOCs than government officials had thought.

As a result, state officials have been looking for ways to supplement the nitrogen oxide cuts in the Houston smog plan with “targeted” cuts in specific VOCs that contribute the most to ozone formation, Saitas said.

When new VOC controls for industry are added to the plan, he said, the current requirement for a 90 percent reduction in nitrogen oxide may be relaxed somewhat.

After Saitas made that statement, agency officials announced this week that they will propose that the environmental commissioners approve adding four rules to the smog plan, setting lower industrial emission limits for 12 VOCs that have been found to react very quickly with nitrogen oxide to produce high ozone levels.

After more scientific analysis, officials will decide later this year whether, and how much, to reduce the 90 percent cut that the plan mandates for nitrogen oxide, commission spokesman Patrick Crimmins said.

Pollution estimates “grossly wrong”

Industry leaders in Houston have complained about the cost and effectiveness of the 90 percent mandate. A collection of prominent petrochemical and utility companies with major plants in the Houston area — including Exxon Mobil, Shell and Reliant Energy — have pursued that argument in a lawsuit against the state plan. They have contended that a better way to reduce ozone is to pare the ordered nitrogen oxide reduction to 80 percent, while adding rules for tighter control of accidental VOC releases.

(The Austin-based Texans for Public Justice revealed this week that companies involved in the lawsuit, responsible for 56 percent of Houston’s industrial nitrogen oxide emissions in 1999, had made campaign contributions exceeding $408,000 to Texas Gov. Rick Perry from 1997-2001, who was lieutenant governor until he succeeded Bush as governor.)

Despite industry efforts to focus regulators’ attention on accidental releases of VOCs, officials at the Texas commission believe that the recent study findings not only reveal underestimates of such unintended emissions, which occur unpredictably and episodically, but also point to a larger problem.

The state’s entire inventory of VOC pollution in the Houston area, which is based on company estimates, is “grossly wrong,” one official said. “There’s a lot more in the air, being emitted daily, routinely on a daily basis.”

“Thousands of valves out there”

For now, there is only informed speculation about the reasons for this apparent underestimation of pollution releases, with most experts focusing attention on the EPA’s methodology for estimating VOC emissions.

“We don’t have any evidence that industry is doing this on purpose,” Daum said in an assertion echoed by regulatory officials.

Saitas said flaws in official EPA estimation methods may be just one part of the problem, however. It’s also possible, perhaps likely, that plant operators aren’t fully aware of the ways their equipment is operating, or it may be functioning outside of normal parameters, he said.

An EPA official, who asked not to be identified, said another explanation may be that federal officials have never pushed state environmental agencies to monitor large pieces of plant equipment that release pollutants, in order to verify emission estimates. Such equipment includes waste-burning flares and cooling towers that remove heat from processed chemicals.

For leaks from smaller but more numerous sources, like valves, Texas has allowed plants to use an emission-calculating method that differs from one the EPA recommends, and this has “probably overestimated the amount of [pollution] control in some cases,” the EPA official said.

An even bigger factor may be the accuracy and completeness of leak-detection surveys, because many plants are so large and complex, the official said. “There’s thousands of valves out there,” he added.

While understated emissions by petrochemical plants may be “a more far-flung problem,” the EPA official suggested that “it won’t be as big a deal anywhere else in the country as it is in Houston, because they have more of a concentration of industry.”

The Philadelphia measurements, taken in 1999, are “not evidence I’d go to court with at this point,” Daum said. But alongside the Houston study, he added, they provide “additional information that these kinds of facilities have [VOC] emissions much higher than reported.”

“Limited events” suggest wider problem

Matt Fraser, one of the academic experts involved in the Houston study, sees evidence suggesting underreported emissions in pollution samples taken elsewhere — specifically, the presence of certain industrially released VOCs in the air just before high ozone levels occurred.

“In cities with smaller industrial complexes, there have been some limited events very similar to the events [that the Houston study tracked] in 2000,” said Fraser, an air pollution specialist on the environmental engineering faculty at Rice University in Houston.

In light of the new VOC findings around Houston, environmentalists in that city complain that a 1995 study of the local ozone problem should have been taken more seriously as a warning that refineries and chemical plants were releasing more VOCs than they were estimating.

“It’s an issue and it’s not being dealt with very well,” said George Smith, a retired dentist who serves as air quality chair of the state chapter of the Sierra Club for Texas. “Everyone’s passing the buck” on whether the EPA’s emission-counting methodology needs adjustment, he said.

The 1995 study, a major foundation for the Houston smog plan signed by Bush, “said there was a problem with the emission inventory, but [Texas officials] and the EPA didn’t follow up on it,” said Jim Blackburn, an attorney representing two Houston environmental groups in a lawsuit seeking to strengthen the plan.

“It could very well reflect on Bush and his people, because they chose to ignore it,” Blackburn said.

The EPA official acknowledged that “in retrospect the [1995] study should have been pursued, but we didn’t have the focus that the airplane flights [in the 2000 study] have given us. It would have been hard to follow up then.”

Help support this work

Public Integrity doesn’t have paywalls and doesn’t accept advertising so that our investigative reporting can have the widest possible impact on addressing inequality in the U.S. Our work is possible thanks to support from people like you.