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Do air emissions from compressor stations pose serious health risks? Pipeline Safety Trust Conference November 21, 2008 Chris Nidel, MS, JD.

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Presentation on theme: "Do air emissions from compressor stations pose serious health risks? Pipeline Safety Trust Conference November 21, 2008 Chris Nidel, MS, JD."— Presentation transcript:

1 Do air emissions from compressor stations pose serious health risks? Pipeline Safety Trust Conference November 21, 2008 Chris Nidel, MS, JD

2 Serious? Risk? serious | ˈ si(ə)rēəs| adjective 1 (of a person) solemn or thoughtful in character or manner : her face grew serious. (of a subject, state, or activity) demanding careful consideration or application : marriage is a serious matter. (of thought or discussion) careful or profound : we give serious consideration to safety recommendations. (of music, literature, or other art forms) requiring deep reflection and inviting a considered response : he bridges the gap between serious and popular music. 2 acting or speaking sincerely and in earnest, rather than in a joking or halfhearted manner : suddenly he wasn't teasing any more—he was deadly serious | actors who are serious about their work. 3 significant or worrying because of possible danger or risk; not slight or negligible : she escaped serious injury. risk |risk|noun a situation involving exposure to danger the possibility that something unpleasant or unwelcome will happen

3 Air Emissions of Concern Formaldehyde - Reasonably anticipated to be a human carcinogen (NTP), genotoxic Acetaldehyde - Reasonably anticipated to be a carcinogen (NTP), genotoxic Acrolein - weakly positive for genotoxic assays PM - respiratory toxicant, cardiac disease NOx, Methane, CO, CO2, - asthma, secondary particulates, greenhouse gases, etc.

4 Dose Makes the Poison? General premise of toxicology that the dose makes the poison The idea is that many things are toxic at some dose However, not all doses of toxic substances have toxic effect

5 Poison Makes the Dose? How general is the general premise? Very little is known about synergistic and compound exposures. Children and other populations may be significantly more susceptible to exposures at the same dose Exposures to genotoxic compounds do not play by the rules

6 Cancer, Genotoxins, and No-threshold Effects Genotoxicity is the presumed mechanism of many carcinogens Theoretically, one molecule of a genotoxic compound (e.g. formaldehyde, acetaldehyde) can cause a mutation --> leading to cancer This theoretical possibility leads to the conclusion that there is no “safe” exposure to genotoxins or carcinogens This means that any exposure creates cancer risk

7 Compressor Station

8 Transco Comer, GA “Actual” emissions estimated using emissions factors from the EPA PollutantEmissions (tons/year) VOCs396.5 Formaldehyde182.3 Acetaldehyde25.65 Acrolein25.69 Methanol8.206 Benzene6.423 NOx PM

9 Emissions Estimates for Compressor Station NOx, CO, and total hydrocarbon (THC) emissions based on testing done in the early 1990’s. VOC component of the THC estimated by EPA database, approximated at 9.31% The “actual” emissions for specific VOCs then estimated using the EPA AP-42 emissions factors

10 Emissions Estimates for Compressor Station NOx, CO, and total hydrocarbon (THC) emissions subject to uncertainty Testing is ~15 years old No information regarding overhaul status or age of equipment at testing vs. current performance VOCs not tested directly EPA’s SPECIATE database is subject to uncertainty in converting THC to VOCs AP-42 Emissions factors used to get individual VOC emissions is limited and may significantly underestimate actual emissions

11 Compressor Age at Transco Station 130 Compressors and Manufacture or Reconstruction Date Mainline Unit 11951Mainline Unit Mainline Unit 21951Mainline Unit Mainline Unit 31951Mainline Unit Mainline Unit 41951Mainline Unit Mainline Unit 51951Mainline Unit Mainline Unit 61951Mainline Unit Mainline Unit 71951Mainline Unit Mainline Unit 81951Mainline Unit Mainline Unit 91951Mainline Unit

12 AP-42 and Uncertainty Canadian study looked at emission from a petroleum refinery Direct testing of emissions using laser based “DIAL” testing Generated an emissions inventory for facility operations and compared to inventory based on AP-42 estimates DIAL measurements showed actual VOC emissions almost 15X AP-42 estimates Dial measurements showed actual benzene emissions 18X AP-42 estimates

13 Emissions vs. Exposure Emissions estimates in tons/year need to be translated into concentrations such as ppm, ppb, or ug/m 3 This is typically done using an air disperson model

14 Air Dispersion Modeling Resulting model is only as good as the inputs, remember, garbage in equals garbage out The emission rates of the pollutants of concern are the most important inputs to the model for its accuracy Also dependent on climatological variables, wind speeds and direction, temperatures, and pressures

15 What We Don’t Know About the Health Risk Uncertainty in actual emissions from facility AP-42 may significantly underestimate or mischaracterize the actual emissions Transco test data may not be representative of current emissions TPH emissions may not be accurately represented by the EPA database No estimates of exposure or dose information from an air dispersion model or equivalent No understanding of individual susceptibilities downwind of the station No appreciable understanding of synergistic or compound risk from multiple exposures

16 What We DO Know About the Health Risk Cancer risk begins even at low exposures Cancer risk for children is estimated at X the risk for adults at the same exposure Respiratory and other effects of exposure to these VOCs may occur at low exposures (e.g. formaldehyde effects in FEMA trailers) Formaldehyde, acetaldehyde, and benzene (carcinogens or reasonably anticipated to be) are released in significant quantities PM and greenhouse gases present both regional and global health risks

17 Is There a Serious Health Risk? There certainly is some risk based on what is known. How serious is that risk? We need a better understanding of the uncertainties that we have identified before we can qualify or quantify the risk Should start with improving our understanding of the actual emissions rates And then use these inputs in an air dispersion model

18 Without Knowing What the Risk Is... The surrounding public should not be subjected to the industry’s experiment - the industry should bear the burden of showing that there is no risk. Currently regulations require almost no control on these emissions - permits merely report emissions older and higher polluting equipment is effectively grandfathered - similar to coal-fired power plants Significant improvements in emissions could be achieved by installing new compressors and: Selective Catalytic Reduction (SCRs) - to reduce NOx emissions Catalytic oxidation equipment to reduce carbon monoxide emissions (yielding more CO 2 however)

19 Conclusions Hazardous emissions from compressor stations have been largely overlooked by current regulations Regulatory programs must be improved to address the “loophole” Short of regulatory programs, pipeline operators should take steps to minimize the threat to neighboring populations as well as the regional and global environment by: better understanding emissions and associated risks upgrading to modern compressors with control equipment increasing the use of engineering controls, such as enclosing compressor facilities and treating or scrubbing compressor emissions


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