Document ID: EPA-HQ-OPP-2010-0923-0020
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2013-07-10T04:00Z

Date:  September 27, 2011

Subject:  Response to Comments on Registration Review for Chlorpropham
(CIPC)

To:  Eric Meiderhoff, Chemical Review Manager

	Office of Pesticide Programs

	Regulatory Public Document (7502P)

	USA EPA

	1200 Pennsylvania Ave. NW

	Washington, DC 20460-0001

From:  William "Bill" A. Keim

	604 Bell Mawr Place

	Barberton, Ohio 44203

Dear Mr. Meiderhoff,

From the information available on the EPA website, it appears that
possibly some clarification can be helpful.  It is not possible to
address every item due to the lengthiness of the explanations.

INTRODUCTION

My practical chemistry began with the application (practice) of academic
chemistry and mathematics when I joined PPG Industries as a Research
Chemist in 1963.  PPG was having some small success with its Sprout Nip
product which is based on CIPC.  Because of my hazard evaluation
experience, I was asked to look at flame arrestors to control torching
which can occur in the generation of the CIPC aerosol process.  Physical
chemistry soon showed this would not work in a reasonable way.  In late
1970s I was given a "cold CIPC aerosol fogging project" which had been
underway for some years.  Cold fogging failed because the aerosol
particles were too large (high residues in the bottom of the pile). 
This project let me see a commercial CIPC thermal aerosol application,
the control experiment.  Several things were obvious.  First, the
aerosol fog was very stable most of the time.  Second, very large
amounts of aerosol were being displaced from the storage bin that was
being treated (2x or double treatments were standard).  Third, it was
amazing how well CIPC inhibited sprouting when so little was known about
what was going on in the application process.  Once again the miracle of
workable chemistry was demonstrated for me.

The observation of an aerosol treatment during the period of Jan 5-9,
1981 led to my development of the Sprout Nip 7A formulation which was
field tested in April 1982.  Subsequent significant activities included:

 I obtained an understanding of potato storage distribution plugging by
Sprout Nip application with Balivi, Boise, ID, in Jan 1985.  I then
instructed all of the applicators to control the air velocity used in
the internal air handling system in order to improve the application
process.

I carried out potato storage evaluation and recommended treatment
procedures with Wilbur-Ellis, Pasco, WA. to improve uniformity of the
CIPC application. 

 I instructed the applicators on the use of reduced air flow planning
for storage treatments beginning with Fred Reeve, Riverhead, Long
Island, NY, in July 1986. 

 I confirmed the correctness of my guidance provided to Wilbur-Ellis and
Fred Reeve which resulted in me writing differential equations for a
mathematical model which very accurately represents the CIPC aerosol
application process.  To date, this math represents the best engineering
analysis for the potato storage treatment. 

 I unplugged Blad Farms potato storages and successfully treated the
potatoes with CIPC aerosol using a very low air flow procedure in Dec
1987.  The normal CIPC treatment procedure that was used at this time
had plugged the storage's air recirculation system.  No air could be
recirculated through the potato pile.  Immediate action was required.  
The duct system had been re-designed by a major potato storage supplier.
 The CIPC applicator had not been told about redesign.  

Papers on my 7A formulation development and the aerosol treatment
process mathematical model are published in ASTM STP 1312, 1996.  These
papers published by ASTM ARE PEER REVIEWED prior to publishing.  Over
the years, potato storages were visited and evaluated with Sprout Nip
applicators in much of the USA and Canada.  I wrote the CIPC Product
Chemistry which was part of PPG's re-registration effort with EPA on
CIPC in the 1980s.  PPG sold the Sprout Nip business about 1987.   

Subsequent contact with the potato industry has confirmed that the
technology that I introduced did exactly what was expected of it. 
Significant aerosol application variables had been identified and some
changes made.  Significantly higher uniformly distributed CIPC residues
were obtained from the use of my innovations in the CIPC application
science.  The risk of failure of the sprout inhibition was significantly
reduced which was the focus at the time.  There was, as expected, still
copious amounts of CIPC displaced to the environment.

As a result of a potato storage fire at Mountain King potato storage in
Monte Vista, CO on 11/26/2000, Bill Keim was once again involved with
CIPC aerosol application.  I was amazed at how little progress in the
commercial aerosol application process there had been in the time that I
was away (actually it looked like some significant backsliding was
occurring).  

Discussions with my sons resulted in our patent application of June 28,
2004 for using potato storage air in the aerosol generation process to
control displacement.  U. S. Patent 7,635,665 for this technology was
issued Dec 22, 2009 and is currently under reexamination by the patent
office.  The reexamination challenge filed for Aceto by attorneys
indicates that the technology must really have some importance to the
potato industry otherwise the patent would be ignored.  The patent is
needed to get financial support to implement this technology which has
significant public benefits.  Alternately, the EPA can support the
implementation of this technology and/or any other technology that KEEPS
THE CIPC INSIDE THE COMMERCIAL STORAGE, PRIMARILY DURING THE CIPC
INTRODUCTION PHASE for the CIPC aerosol application process to stored
potatoes.  So far any work on this technology has only generated
expenses.   

Environmental Fate and Effects Division (EFED) Response 04/14/11

The Aerobic Soil Metabolism data can also be helpful to assess the fate
of CIPC in potato storages and the potato samples taken for analysis. 
Residual soil life of CIPC for weed control is poor.  Please make
details of the work available to the public.  

Thanks for recognizing the need to "minimize the escape of the
compound".  However, after normal housekeeping for a treatment, the
majority of displacement is caused by the air pump (typically 140 cubic
feet per minute) that is part of the aerosol generation equipment. 
Aerosol generation/introduction times are generally an hour or longer,
and most displacement occurs during aerosol introduction to the potato
storage.  The aerosol hopefully persists as visible smoke in the air
space of the storage for one or more hours after introduction.  Potato
air re-circulation should be maintained at a low rate during the period
of deposition of visible aerosol.  Deposition is over when a visible
aerosol is no longer present (see the applicable physical chemistry).  

I worked continuously with the applicators, particularly after 1980. 
PPG's label was adjusted to reflect technology improvements and to help
control how the applicator did his job so that it was performed
properly.  The use of application equipment was monitored.  Still, the
independence of the applicator provided some surprises.  After PPG sold
the CIPC business unit, there were label changes made that actually
eliminated most of the controls that PPG put in place.  Today’s CIPC
label essentially lets the applicator do whatever he wants when applying
the CIPC as it has little if any controls on it that should be in place
to protect the human population and the environment. 

If displacement does not provide the answer for "where is the missing
CIPC?" then degradation is a likely candidate.  I once obtained a
residue of CIPC from a fan shroud in a potato storage that contained
about 10% of the urea, di-(3-chlorophenyl) urea.  Other expected
degradates can be expected to remain in vapor state.  Some of these
vapors will of course dissolve in the potatoes.

Health Effects Division (HED) Response 17-May-2011

First Paragraph of the letter response on page 3-4:  Large amounts of
CIPC are displaced because of the air pump used with typical aerosol
generation equipment to pump outside air into the storage.  Directions
for use on the label do not address this air flow rate or the feed rate
of CIPC for the aerosol generation equipment.  Directions for use of
many pesticides provide guidance on the amount of water to be used in
the applied spray.  What is the difference?

Fourth Paragraph under CIPC Application:  There seems to be some
confusion with respect to the residue data being discussed.  Our concern
is with residues used to evaluate a treatment with CIPC which are used
to approve registration.  We think that our comments with respect to
these data are valid.  Data for residues on potatoes as actually
consumed are also important to the registration process, but are not the
subject of our comments.

Fifth Paragraph under CIPC Application and First, Second and Third
Paragraphs under Sampling:  Does the residue information used address
the concerns that were expressed about handling potato samples?  Data
available to me does not appear acceptably useful to do mass balances on
the application process.  As a chemist, we are trained that you can
track where everything goes in a chemical reaction using a MASS BALANCE.
 The use of a mass balance is critical to evaluating the CIPC process
and the CIPC registration process.  EPA needs to require all of its
registered CIPC label holders to submit a mass balance for the CIPC used
during their respective application processes in order to know where the
CIPC goes.  Then it needs to check to make sure that this process was
performed properly.

Sixth Paragraph under CIPC Application:  It would be nice to think that
the temperatures used for melting CIPC are kept reasonably low and the
exposure times short.  Temperatures exceeding 180 ºF have been
observed.  This time at elevated temperature can last many hours.

Seventh Paragraph under CIPC Application:  Does OSHA have the ability to
stop use of an EPA approved labeled product?  

Technologies Sciences Group (TSG), Inc. Response Feb 18, 2011

Aerosol Application Process as described by TSG:  "The chlorpropham is
applied from outside the building through a small tube into the
building's ventilation ducts, using a sealed thermal fogging delivery
system.  During this application process, chlorpropham is not released
into the environment."

Clearly the exact equipment described by TSG should be that required for
applications of CIPC and its specification required by EPA on the
product label.  All Leco and Tifa based equipment use must be prohibited
if they use an air pump to put outside air into the potato storage
during aerosol generation which causes CIPC displacement.  TSG implies
that they don’t use any air pumps to pump outside air into the storage
(if they did there would be gross displacement of CIPC from the
storage).  If so, then TSG please share the necessary identification of
this aerosol generation equipment with the EPA so that it can be
specified on the label.

Letter of Joel Micka, JMC Enterprises, Inc., of March 31, 2011

I think that I am aware of the aerosol generation equipment of JMC from
discussions with Dr. Gale Kleinkopf.  I do not know specific details for
the equipment.  If I were to observe applications with JMC equipment, I
expect that I could assess its capability and evaluate the total process
(think total quality).  From the claim for "virtually NO escape of CIPC
during a potato storage thermal fogging treatment with our application
technology" in the letter one would expect that the EPA would also want
to have this equipment for application on CIPC specified on the product
label along with TSG specified equipment. 

Letter Michael D. Lewis of April 1, 2011

Lewis knows about the air pumps on Leco and Tifa based aerosol
generation equipment and the displacement of CIPC.    He also can be
expected to know about JMC equipment.  Surely some applicator has given
him a copy of my Sprout Nip Aerosol Application Field Handbook, issued
in April 1987.  Copies should also be available through records of some
potato storage fire lawsuits.  I worked with lawyers of a legal firm who
understand the Handbook very well.  I cannot understand the scientific
basis for most of the Lewis comments.  Possibly EPA needs to have both
of us (or others equally qualified) as consultants to get a good
understanding of CIPC application.

I too think that CIPC is very critical to the potato industry.  We just
need to clean up displacement.  We are going to have to accept some
degradation.  It is Mother Nature's way.  She really is the one who
makes the rules.

Letter Dale E. Nelson, Nelson's Vegetable Storage Systems Inc., of April
2, 2011

Nelson's History:

The 3 lb ai per gallon CIPC product was the Emulsifiable Product for
water spray application to fresh market potatoes.

The methanol containing product was Sprout Nip 7A, formulated by me. 
PPG chose 7A over the solid material for the formulation as it is
essentially the same but is more easily handled as a liquid.  I now
recognize that some degradation is much easier to control with 7A versus
the 4A.   Methanol replaced isopropanol and propylene glycol in a 4A
product.  Using methanol, a Leco machine can process 42 lbs of CIPC per
hour versus 20 lbs of CIPC per hour with 4A.  A Tifa machine can process
about 63 lbs of CIPC versus 20 lbs of CIPC per hour with 4A.

Comments:

Bill Keim started in 1986 the use of the necessary air velocity control
in a potato storage which occurs when fan speed is reduced.

A realistic understanding of the autoignition process in CIPC aerosol
generation process was developed.  If the food grade adjuvant used by
Nelson is clove oil, then Nelson can have more risk of autoignition.

I would expect that Nelson, who started as an applicator in Idaho in
1979, should know me from my visits to PPG Idaho applicators.  

It is very easy to lose a lot of CIPC and still get a successful
treatment.  CIPC is amazing for potato sprout inhibition in spite of our
application technology ignorance.

If I knew the details of NVSS application process, then I think that I
could provide a reasonably detailed scientific explanation for its
success.  It can be expected to be explained by reasonable physical
chemistry.  Part of BP's gulf oil release problem was due to the poor
use of physical chemistry.

The remaining major area for improvement in CIPC use on potatoes appears
to me to be how much to use in the application (the use rate) and the
identification of potato and/or potato storage variables significant to
the application with appropriate recommendations.  Problems with
understanding the application process and implementing the changes
needed have made progress on these other issues practically
non-existent.  The use rate of CIPC can be expected to get much lower. 
The unnecessary requests for higher use rates are still being made.   
The goal needs to be to get to the use rate amounts necessary to get the
necessary sprout inhibition while minimizing any excess amounts.

CONCLUSION

Can the need for EPA to "Hire knowledgeable consulting guidance on CIPC
aerosol technology for potatoes." be more apparent? 

Sincerely,

William A. Keim

Keim Aerosol Technologies

604 Bell Mawr Place

Barberton, OH 44203

330-805-6453

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