Meeting Minutes:  December 11, 2007 

Sulfuryl Fluoride - Exposure Discussion;  EPA (OPP, OAR) & Dow
AgroSciences, Exponent

Recorder:  Meredith Laws

	      Registration Division, OPP

Introduction:  M. Laws stated that there was no set agenda for the
discussion.

                       Dow expressed appreciation and acknowledged the
complexities of the issues with SF and noted that the SF risk assessment
and exposures are unique.  Dow asked about the goal of the mtg being the
discussion of the exposure assumptions, changes that have been made, and
the steps forward.

Discussion of OPP, HED handouts:	M. Doherty, EPA: provided handouts:  a
spreadsheet and tables of the dietary exposure assumptions.  We are
looking at what Profume uses are driving exposure to fluoride, space
fumigation + direct food fumigation.  Spread sheet shows drivers at top
(totals 9 pages long but quickly drops off so not all pages provided).

	M. Doherty noted the cryolite piece on the bar chart comes from grapes
and that space fumigation = low amount of food (fraction) treated. 
Under food – most commodities assumed 100% treated (id’d as “1”
in the fraction column).

	R. Keigwin noted that OPP has a new food handling model – but it has
not been tested for fumigants yet.  Focus has been on crack & crevice
treatment.

	Attendees discussed the spread sheet and what columns meant. 
“Other” on the bar chart are items such as coffee, grapes, etc. 
Cryolite – only “cross over” group to Profume is still
raisins/grapes.

Discussion of how the commodities are used in DEEM:   M. Doherty:  the
spread sheet represents those numbers used in the January, 2006 risk
assessment.  Since the NAS report, some new exposures, ie.  we (EPA)
underestimated exposure from water.

Dow believes the NAS report has a different view of exposures from
water.  Two liters/day is the Agency’s default consumption value,
which represents about the 95th percentile.  Our January 2006 chronic
assessment used the average consumption in DEEM (about 0.7 L/day) and 2
ppm as the fluoride level in direct drinking water (i.e., tap water). 
NAS stated this level is too low due to a significant portion of the
population being exposed to more than 2 ppm (about 1%) and some exposed
to more than 4 ppm (about 0.07%).   

NAS report:  EPA underestimated powdered tea.  And, EPA used 1995 paper
on consumption of toothpaste, but a 1999 paper by the same author said
consumption of toothpaste went up, EPA should use this.

Dow presentation:  “Profume Exposure Refinement”.  Noted that Dow
was asked to present current picture today and expected picture:

Structural Fumigation:  mills & processors fumigated 2-3x/year.  Not
practical to remove the food but get it down as low as possible. 
Referred to as incidental fumigation on the label.

Food Fumigation:  food is placed in a chamber and directly fumigated. 
MeBr use: walnuts, hams, cocoa beans, beans-dried, plums, dates.  Other
would be when there is a pest infestation.  Dow noted there is interest
in seeds to be planted.

Background:  Reg. Milestones:  1997 – Dow initiated development;  2002
– EUP granted, never used;  2004 – Profume registered, 35%  risk
cup;  2005 – Amended registration, 43% fluoride risk cup;  2006 –
NAS report completed.  How does the risk cup change with the NAS report?

Dow:  this is a unique product and use pattern.  Dow has use and usage
data, periodic updates submitted to BEAD.  Opportunity for unique
refinement.  Built as a methyl bromide replacement – well understood
use pattern.  Stratospheric Ozone Protection – Profume/Dow recognized
by EPA.

Methyl Bromide Phase Out:  over ~ 6 years, transition.  

US pop exposure 2004 vs 2006 assessment:  Profume contribution of total
fluoride jumped, ie. 0.8% - - - > 18% but the 18% can be refined.  Or: 
0.0003 mg/kg/day - - -> 0.0079 mg/kg/day (0.0007, structural + 0.0072,
food)

Dow noted that the NAS report recommends a probabilistic analysis, asked
if we had thought about this.  HED has never done a probabilistic for
chronic risk, has done it for acute.  Dow notes most risk assessments
don’t have 6 different routes of exposure w/ pesticides least.  EPA
stated that we haven’t had the tools to do a probabilistic.

Exponent asked for OW’s timeline for review of the NAS report.  EPA
meeting participants unsure, noted that OW not required to do a full
aggregate.  Other sources may affect the MCL.  Intentional fluoridation
– where something can be done.  M. Doherty noted that it is very
difficult to remove naturally occurring fluoride.

General comment:  future assessment:  base exposure on data vs.
assumptions

Exponent requested EPA’s idea of timing.  EPA participants could not
answer legal response timing.  Dow will offer a proposal to EPA – may
provide a new assessment w/ all the new assumptions & info, incorporate
new details.

HED staff stated that they need to investigate their drinking water
data, what they have, ie. data from 16 states – what does this mean
nationally.  New data from 48 states?

Private wells are not reported.  Public water – need to report if > 2
ppm, the secondary MCL.  EPA assumes that what is reported is the same
all year long, if it changes temporally – we could adjust but we
don’t know if it does.  

HED noted that OW has 2 things to do:  review the NAS report and also
the normal 6 year review includes fluoride (revise MCL or no?  Safe
Drinking Water Act – 48 states data submitted).  2009, 2010 prob
before MCL will be looked at, but legal process may go faster.

