Setting the Bar Low on Houston Air Quality

The Pump Handle passes along a news report that Bill White, the mayor of Houston is crossing swords with Lyondell’s refinery over benzene emissions. He wants the refinery to achieve further emissions reductions, and wants the Texas Commission on Environmental Quality to monitor more stringently emissions and fenceline concentrations in air. Benzene emissions from the refinery are below TCEQ permit limits, but the story in the Houston Chronicle says it’s not clear how those limits were developed.

I’m for reducing emissions to as low as reasonably achievable, because it’s a sign that you’re committed to the best industrial practices. However, there's another perspective here. When the Mayor's own task force on Houston air quality concluded:

Air pollution levels in the City of Houston are considered to be unacceptable by knowledgeable experts and the general public and are likely to cause air-pollution related health effects for Houston residents. Pollutant levels are driven by many sources including: tailpipe emissions from cars, trucks and buses; toxic pollutants emitted into the air by more than 400 chemical manufacturing facilities, including 2 of the 4 largest refineries in the U.S.; the petrochemical complex along the Houston Ship Channel and the Port of Houston; and many small operations spread geographically across Greater Houston, such as surface coating processes, dry cleaners, gas stations, printing processes, restaurants, charcoal barbecues, and gasoline-fueled lawn maintenance equipment,

what does he hope to accomplish by singling out Lyondell?

The leaders and citizens of Houston and the state of Texas made their choices long ago to become "business-friendly" which correspondingly meant a lack of commitment to environmental quality; they also chose to become highly reliant on motor vehicles (which by the way are probably the more widespread and significant sources of exposure to air toxics such as benzene). If Mr. White is really interested in improving air quality and public health in Houston, he really should be aiming his sights a little higher than one oil refinery. Lyondell could reduce its benzene emissions to zero and I would defy anyone to show any meaningful reduction in community exposure to benzene, without any action to control the mobile and area sources. I suppose focusing on Lyondell is a start, but at the same time, couldn’t he try to persuade Houstonians not to drive their cars so damn often?

Don’t Send and Attorney – An Update on Air Toxics Emissions

I wanted to quickly return to this topic, before I go out on the road again, and before it gets lost amidst more urgent matters (cell phone- and obesity-induced disappearing honeybee terrorism global warming metabolic syndrome, or something like that).

Last month, I took to task the Environmental Integrity Project for presenting an incomplete picture of the risks from emissions of toxic substances to the air from oil refineries. The Project’s report Refined Hazard" discusses the Toxic Release Inventory (TRI) reports submitted to EPA specifically from oil refineries. Specifically, the report examines "OSHA carcinogens", which refers to whether or not a chemical will be identified on the Material Safety Data Sheet as a carcinogen. It provides a "top ten" list of refineries in terms of emissions of OSHA carcinogens, and concludes that, while emissions of carcinogens have declined on an industry-wide basis between 1999 and 2004, there have been substantial increases at some facilities over the same time period. Finally, the report raises questions regarding the accuracy of TRI reporting.

The report acknowledges that TRI data do not reveal actual levels of public exposure to those chemicals. However, this understanding appears to be honored more in the breach; for example, statements such as these can be found in the report:

For example, the La Gloria refinery in Tyler, Texas, was the fourth largest emitter of OSHA carcinogens in 2004, but at 55,000 barrels per day, it is ranked 95th in overall production capacity. La Gloria’s 2004 releases of benzene, a known human carcinogen, at 117,890 pounds, far exceeded those from refineries several times its size. Two small Kansas refineries, National Cooperative Refining Association (“NCRA”) and Coffeyville Resources Refining and Marketing, were also notable for their disproportionately high releases of OSHA carcinogens.

Ok, so we can see that emissions controls may not be as tight in smaller facilities compared with larger facilities run by the major oil companies. Not a real surprise. But what's this mean in terms of potential human exposure?

Probably not as much as you would think. Two major well-conducted studies on exposure to airborne contaminants, the TEAM (Total Exposure Assessment Methodology) Study, completed by the EPA in the 1980s, and the Relationships of Indoor, Outdoor, and Personal Air (RIOPA), published in 2005, suggest that outdoor emission sources might not dominate our exposure to emissions to the air from stationary sources such as refineries. Some sound bites from the RIOPA report:

The investigators measured indoor, outdoor and personal exposure concentrations (from air sampling monitors that people wore) in adult residents in each of three cities with different air pollutant sources and weather conditions: Los Angeles, CA, Houston, TX and Elizabeth, NJ. Homes were selected by distance from various sources.

The homes and subjects selected did not proportionally represent the greater population. Rather, homes close to sources were preferentially sampled in order to examine the impact of possibly high exposures.

So, this study was designed to evaluate the potential influences of stationary source emissions on exposure to air toxics. What it concluded was:

With a few exceptions, mean and median personal exposures and indoor concentrations of VOCs and carbonyls were higher than the outdoor concentrations within each city and for the whole data set. Personal PM2.5 concentrations were higher than indoor and outdoor concentrations. The finding that personal exposure concentrations were higher than outdoor concentrations for many compounds indicates that indoor sources contribute to and in some cases dominate, personal exposures; this is consistent with the results from other studies.

This is consistent with the TEAM study results, which concluded that bringing home dry cleaning, using self-serve gas stations and storing gas cans in your garage, using municipal water supplies that were chlorinated, and having “moth balls” in your home were more important sources of inhalation exposure to tetrachloroethylene (perc), benzene, chloroform and para-dichlorobenzene, than industrial sources. I have yet to see these findings reflected in air toxics control strategies (which are focused on reducing stationary source emissions), and to this day, I don’t understand why that is.

Don’t Send an Attorney. . .

. . . to do a scientist’s job. I have no doubt that the staff of the Environmental Integrity Project are fine environmental attorneys. Just a reminder though: emissions do not correspond to exposure or risk. More on this later, because now I have to go through their refinery carcinogens report and line it up with the National Air Toxics Assessment and the Urban Air Toxics Monitoring Program. Be back soon.