Do air emissions from compressor

stations pose serious health risks?

Pipeline Safety Trust ConferenceNovember 21, 2008Chris Nidel, MS, JD

Serious? Risk?• serious |ˈsi(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

Air Emissions of ConcernFormaldehyde - 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.

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

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

Cancer, Genotoxins, and No-threshold EffectsGenotoxicity 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

Compressor Station

Transco 130 - Comer, GA“Actual” emissions estimated using emissions factors from the EPA

Pollutant Emissions (tons/year)

VOCs 396.5

Formaldehyde 182.3

Acetaldehyde 25.65

Acrolein 25.69

Methanol 8.206

Benzene 6.423

NOx 4143.4

PM10 73.7

Emissions Estimates for Compressor StationNOx, 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

Emissions Estimates for Compressor StationNOx, 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

Compressor Age at Transco Station 130Compressors and Manufacture or Reconstruction

DateMainline Unit 1 1951 Mainline Unit 10 1958

Mainline Unit 2 1951 Mainline Unit 11 1959

Mainline Unit 3 1951 Mainline Unit 12 1962

Mainline Unit 4 1951 Mainline Unit 13 1962

Mainline Unit 5 1951 Mainline Unit 14 1968

Mainline Unit 6 1951 Mainline Unit 15 1969

Mainline Unit 7 1951 Mainline Unit 16 1971

Mainline Unit 8 1951 Mainline Unit 17 1980

Mainline Unit 9 1951 Mainline Unit 18 1990

AP-42 and UncertaintyCanadian 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

Emissions vs. ExposureEmissions estimates in tons/year need to be translated into concentrations such as ppm, ppb, or ug/m3

This is typically done using an air disperson model

Air Dispersion ModelingResulting 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

What We Don’t Know About the Health RiskUncertainty 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 equivalentNo understanding of individual susceptibilities downwind of the stationNo appreciable understanding of synergistic or compound risk from multiple exposures

What We DO Know About the Health RiskCancer risk begins even at low exposuresCancer risk for children is estimated at 10-100X the risk for adults at the same exposureRespiratory 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 quantitiesPM and greenhouse gases present both regional and global health risks

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 riskShould start with improving our understanding of the actual emissions ratesAnd then use these inputs in an air dispersion model

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 CO2 however)

ConclusionsHazardous emissions from compressor stations have been largely overlooked by current regulationsRegulatory 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