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dithiopyr (Dimension) NYSDEC Conditional Registration 12/93

New York State Department of Environmental Conservation
50 Wolf Road, Albany, New York 12233

                                         DEC 30 1993


Mr. Stephen A. Adams
Senior Registration Specialist
Monsanto Company
800 N. Lindbergh Boulevard
St. Louis, MO 63167

Dear Mr. Adams:

Re:  Registration of Dimension Turf Herbicide (EPA Req. No. 524-431)

     Monsanto submitted to this Department an application to register 
Dimension Turf Herbicide (EPA Reg. No. 524-431), containing the active 
ingredient dithiopyr on September 12, 1991. Dimension is an herbicide 
for control of annual grasses and broadleaf weeds on turfgrasses in 
lawns and ornamental turf.

     This Department and the New York State Department of Health have 
reviewed all of the information submitted in support of this 
registration. We are concerned about potential impacts on ground water, 
particularly in vulnerable areas of this state. Laboratory and field 
studies do not adequately define the leaching characteristics of 
dithiopyr and its metabolites. Modeling results and calculations (based 
upon field studies) performed by the Department of Health indicate that 
groundwater concentrations of dithiopyr and its metabolites could 
approach or exceed the potential groundwater standard of 25 micrograms 
per liter (mcg/L (dithiopyr) and 50 mcg/L (each metabolite). The 
metabolites of dithiopyr are expected to be mobile in soils and results 
of the California field dissipation study support our concern that soil 
sampling alone cannot be used to define the leaching potential of 
soluble chemicals. Concerns about potential impacts on groundwater are 
heightened by dithiopyr's relatively high toxic potency (demonstrated in 
chronic animal feeding studies) and the lack of chronic toxicity studies 
for its metabolites.

     In view of the above, the Department will approve a conditional 
restricted use registration of Dimension. This product is classified as 
a restricted use pesticide due to the statement on the federal label 
"Professional Turf Applicator Use Only" and because there are 
outstanding environmental fate concerns to be addressed by the 
conditional registration.

     As a condition of registration:

1.  Dimension Turf Herbicide is not to be sold, distributed, or used on
    Long Island due to its high population density which is exclusively
    dependent upon groundwater as a source of drinking water, porous
    soil conditions, and vulnerable aquifer. Monsanto must provide a
    label to this Department noting that Dimension Turf Herbicide is not
    for use on Long Island prior to marketing this product within New
    York State. This label can be either an amended federal label, or a
    special local need label for registration only in New York State.

2.  Monsanto must conduct a field lysimeter study (leachate and soil
    sampling), under soil type and conditions to be specified in advance
    by this Department, to address remaining concerns about potential
    ground water contamination. Prior to initiation of said study,
    protocols must be approved by this Department. Upon completion and
    review of the study, the registration of Dimension in New York State
    will be re-evaluated.

3.  Monsanto must provide this Department with a copy of the final
    results, when available, of the MON 13200 aquatic plant study, which
    the registrant is using to support the contention that aquatic
    macrophytes will not demonstrate a greater sensitivity than algae to

     In the event that Monsanto does not wish to have the label use 
directions reflect the Long Island prohibitions, this Department is 
prepared to promulgate a rule reflecting this limitation. If this option 
is to be pursued, the registration will be issued upon the final rule 
taking effect. A rulemaking process could be expected to take nine 
months to one year.

    Since this product is classified as a restricted use pesticide, 
please note that New York State Environmental Conservation Law (ECL) 33-
0901.1 states that: "A commercial permit is required for the 
distribution, sale, offer for sale, purchase for the purpose of resale 
or possession for the purpose of resale of a restricted use pesticide."

     A review of our records indicates that Monsanto does not possess a 
currently valid Commercial Permit.

     If Monsanto proposes to sell or offer for sale any restricted use 
pesticide to any person within New York State, a commercial permit is 
required for both Monsanto and the purchaser. ECL 33-0905.1 further 
states that: "Any person who engages in...the sale of restricted use 
pesticides shall be certified by the Commissioner..."  Commercial permit 
holders must employ or retain under contract at least one person who is 
certified in New York State for the application of restricted use 

     Information is enclosed pertaining to commercial permits in New 
York State along with an application form for your convenience. 
Questions regarding commercial permits and certification should be 
directed to Ms. Marilyn DuBois, Chief, Bureau of Pesticide Regulation at 
(518) 457-7482.

     The approved label is the federally registered label as submitted 
with the addition of a restriction prohibiting sale, distribution or use 
on Long Island. Enclosed is the Certificate of Pesticide Registration. 
Please supply this office with the requested label.


                             Norman H. Nosenchuck, P.E.
                             Division of Hazardous Substances


cc: w/encls.- D. Rutz - Cornell
    w/encls.- D. Rapp - N.Y.S. Dept. of Ag. and Mrkts.