Transcript Revision to AAL for H2S

Acceptable Ambient Level
Hydrogen Sulfide
EMC Air Quality Committee
12 February 2003
by
Preston Howard, President
Manufacturers & Chemical Industry
Council of North Carolina
MCIC
MCIC
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
MCIC
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
MCIC
Responsibilities
SAB - Risk Assessment
• No considerations other than science
EMC - Risk Management
• Practical considerations
• Technical feasibility
• Economic impact
MCIC
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?
MCIC
H2S Emissions in North Carolina
Figure 1
Hydrogen Sulfide Emissions in North Carolina
Targeted Industry
6,412,620 lb/yr
16.16%
Asphalt Industry
204,913 lb/yr
0.52%
Municipal WWTP
(not a targeted industry),
17,660 lb/yr
0.04%
Animal Husbandry
(not a targeted industry)
33,046,201 lb/yr
83.28%
MCIC
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
MCIC
Conflicting interpretations of
Jappinen’s results
 SAB

Concluded that the
bronchial obstruction
experienced by 2 of
the 10 asthmatics
constituted an
asthmatic response
 Jappinen

noted that the
“increase [in
bronchial obstruction]
was not statistically
significant and did not
result in clinical
symptoms”
MCIC
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”
MCIC
Vickie L. Tatum, Ph.D.
 “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
MCIC
[the] effects of H S
Others
 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”
MCIC
“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,
MCIC
appeared to play a role
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

MCIC
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
MCIC
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”
MCIC
Vanhoorne . . .
 Since Vanhoorne involved the co-exposure
of H2S and CS2, and since EPA has indicated
that the use of studies involving such coexposure 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
MCIC
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
MCIC
What should the EMC do?





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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
MCIC
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
MCIC
EMC’s Role as RISK MANAGER
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

MCIC