Acceptable Ambient Level Hydrogen Sulfide - PowerPoint PPT Presentation

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EMC Air Quality Committee 12 February 2003 by Preston Howard, President Manufacturers & Chemical Industry Council of North Carolina MCIC.

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Acceptable Ambient Level Hydrogen Sulfide

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Acceptable ambient level hydrogen sulfide l.jpg

EMC Air Quality Committee

12 February 2003


Preston Howard, President

Manufacturers & Chemical Industry

Council of North Carolina


Acceptable Ambient Level Hydrogen Sulfide

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6 Affected MCIC Members Sites - All in Economically Depressed Regions

  • Blue Ridge Paper - Canton

  • International Paper

    • Riegelwood

    • Roanoke Rapids

  • PCS Phosphate - Aurora

  • Weyerhaeuser

    • New Bern

    • Plymouth

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All are Major Economic Hubs

  • Directly employ from 500 to 1200 on-site

  • Statewide 9000 total jobs

  • Thousands of “spin-off” jobs

  • Annual payroll $494 Millon

  • $750 Million in purchases from NC vendors

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  • SAB - Risk Assessment

    • No considerations other than science

  • EMC - Risk Management

    • Practical considerations

    • Technical feasibility

    • Economic impact

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Regulated Sources

  • Six sites owned by MCIC member companies = 14% of all H2S emissions in NC

  • 86% of H2S emissions would not be subject to the new AAL

  • Is it prudent to spend $500 Million to control 14% of the emissions?

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H2S Emissions in North Carolina

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Jappinen et al. 1990

  • “to assess the possible effects of low concentrations of H2S on respiratory function”

  • Exposed 10 asthmatics to 2 ppm for 30 min.

  • 2 ppm = 2700 ug/m3

  • current AAL is 2100 ug/m3

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Concluded that the bronchial obstruction experienced by 2 of the 10 asthmatics constituted an asthmatic response


noted that the “increase [in bronchial obstruction] was not statistically significant and did not result in clinical symptoms”

Conflicting interpretations of Jappinen’s results

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Bruce Dalton, MD, FACOEM

  • “Jappinen study findings are consistent with population studies of residents living near industrial sources of hydrogen sulfide”

  • “the SAB’s recommendations are based on interpretations of the Jappinen study that are inconsistent with the data as published”

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“The SAB implies ...that exposure to low levels of hydrogen sulfide trigger asthma attacks . Such conclusions are not supported by the scientific and medical literature, nor are they shared by other bodies.”

Michigan Environmental Science Board interpreted Jappinen - “asthmatic subjects [are] not more susceptible to [the] effects of H2S

Vickie L. Tatum, Ph.D.

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  • 1997 American Conference of Governmental Industrial Hygienists - “studies on respiratory function of pulp mill workers and asthmatics at 2 ppm hydrogen sulfide failed to find a statistically significant change produced by the hydrogen sulfide”

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“Real world” studies…

  • 11 different studies on respiratory health of residents near pulp mills and refineries

  • 10 studies found no evidence of significantly increased incidence of asthma or asthma-like symptoms

  • 1 study found increased incidence of asthma, but authors noted that other factors, such as mold in homes and pollen, appeared to play a role

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The 1 hr AAL derived from Jappinen should be discounted

  • Is not supported by Jappinen (the author)

  • Is not supported by scientific and medical literature

  • Is not supported by interpretations by other government agencies (Michigan ESB)

  • Is not supported by American Conference of Government Industrial Hygienists

  • Is not supported by population studies of residents living near industrial sources of H2S

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Vanhoorne et al. 1995

  • Basis for SAB’s 24 hr AAL of 33 ug/m3

  • Study of eye irritation complaints among workers at a viscose rayon plant

  • Workers were exposed to both hydrogen sulfide and carbon disulfide

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Quotes from Vanhoorne. . .

  • “the prevalence of eye complaints… is clearly associated with exposure. However, deciding which of the two suspected agents, H2S or CS2, was responsible proved impossible in this study.”

  • Last year EPA judged studies like Vanhoorne to be “unsuitable” due to the “co-exposure to other chemicals like CS2”

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Vanhoorne . . .

  • Since Vanhoorne involved the co-exposure of H2S and CS2, and since EPA has indicated that the use of studies involving such co-exposure is inappropriate, MCIC believes that the EMC should disregard the Vanhoorne study and the proposed AAL of 33 ug/m3 that was derived from it

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MCIC Position

  • The SAB offered a 24 hr AAL of 120 ug/m3, based on Brenneman study

  • MCIC’s experts have reviewed this derivation

  • Scientific disagreement over the Brenneman study is not extensive

  • MCIC believes that compliance with this 24 hour AAL is achievable at reasonable cost, if accompanied by an exemption for WWTP

  • MCIC has no objection to adoption of 120 ug/m3 (24 hr), with WWTP exemption and compliance 5 years following permit renewal

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What should the EMC do?

  • We know from staff about the severe economic hardship associated with 56 ug/m3 (1 hr)

  • We know there is considerable disagreement in the scientific and medical communities

  • Scientific complexity/disagreement causes confusion

  • Confusion breeds a tendency to “defer” the decision to the science experts - the risk assessors

  • Urge you not to shirk your risk MANAGEMENT responsibility by deferring a management decision to risk ASSESSORS

  • This decision is rightfully made by the EMC - you are the risk MANAGERS - you should decide the appropriate AAL

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High regard for SAB

  • DR. Lucier and his colleagues on the SAB are well respected

  • Our purpose here today is not to criticize the SAB

  • To the contrary, our purpose is to note for you that knowledgeable scientists and medical professionals disagree on the health effects of low level H2S exposure

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  • Weigh the merits of the scientific arguments and assess the scientific uncertainty and disagreement

  • Consider the significant economic implications for the 4 companies as well as for entire regions of North Carolina

  • Assign an AAL that affords adequate protection for the public health without unnecessarily jeopardizing the jobs of working families

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