UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MAY 14 2012 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: 

FROM: 

BEAD Chemical Profile for Registration Review: Dazomet (035602) 

Leonard Yourman, Plant Pathologist ,tA1~ 

THRU: 

Biological Analysis Branch .- { 1. 

Sepehr 

Science 

Haddad, 

Information 

Environmental 

and Analysis 

Protection 

Branch 

Specialist /tr.J' 

I ~ 

Derek Berwald, Economist W /0 1J./\..\fS Economic Analysis Branch UJ 

Biological and Economic Ana sis Division (7503P) 

Arnet Jones, Chief 

Biological Analysis Br c 

Diann Sims, Chief A ·1Z 1L.~<.¥-""'" Science Information and Analysis Branch 

Timothy Kiely, Chief ~ wt r -0 

Economic 

Biological 

Analysis 

and Economic 

Branch 

Analy is Division 

~ 

(7503P) 

TO: Dana Friedman, Chemical Review Manager 

Risk Management and Implementation Branch 2 

Pesticide Re-evaluation Division (7508P) 

Product Review Panel date: May 2,2012 

INTRODUCTION 

The purpose of this document is to convey usage information and a broad overview of the pest 

management roles of pesticides that are beginning to undergo registration review. The 

anticipated audience consists of the team of EPA staff currently evaluating the registration status 

of dazomet, and eventually the general public. This document builds upon the data already 
provided in the "Usage and Label Use Data Packages" that are also provided to Registration 

Review teams by BEAD. The document is based on information and data available to BEAD as 

of April, 2012. 

Dazomet [Basamid®] is a non-selective soil fumigant with fungicidal, herbicidal and nematicidal 

properties (RED-FS, 2008). Soil fumigants form gasses when applied to soil. Once in the soil, 

the fumigants work by controlling pests that can disrupt plant growth and crop production. 

When dazomet is applied, it is quickly broken down into several degradates; the major degradate 

being methyl isothiocyanate (MITC). MITC is highly volatile and is responsible for the 

fumigant properties of dazomet. Dazomet is used on a wide range of sites including golf greens 

or tees, nonbearing crops, turf sites, ornamental sites, field nurseries, compost piles, potting soils, 

and strawberries and tomatoes (in California only). Under moderate soil temperature and 

moisture, dazomet has been successful in replacing such former methyl bromide-uses as 

turfgrass removal for golf courses that were undergoing renovation (e.g., Brecke et al., 2005). 

Dazomet uses that have successfully replaced methyl bromide can be considered to have high 

benefits. 

COMMON FORMULATIONS AND APPLICATION METHODS 

Generally, dazomet uses fall into two basic categories, soil fumigation or antimicrobial use. For 

soil fumigation, the formulation is granular, and for the antimicrobial use the formulation is 

pelletedltableted, liquid (soluble concentrate and flowable concentrate) solutions, water soluble 

packaged solids, and ready to use solutions. 

USE SITES 

Dazomet is labeled for both agricultural and non-agricultural uses. There are no residential uses 

of dazomet. Dazomet was first registered in the United States in 1967 as an algaecide, a 

bacteriostat, and a microbiocide in a variety of commercial and industrial applications such as 

pulp and paper mills, cooling tower waters, and non-food adhesives. In the late 1980s pre-plant 

soil uses of dazomet were registered. Unlike other soil fumigants, dazomet is applied as a dry 

granule and incorporated into the soil or applied to the soil surface and watered into the soil to 

activate it (US EPA, 2009). 

Agricultural Use Sites 

Agricultural sites are for soils of nonbearing fruit and nut trees. It is also labeled for use on soils 

for strawberries and tomatoes only in California. 

Non-Agricultural Use Sites 

Dazomet is labeled as a soil fumigant on the following sites: golf greens and tees, sites, turf sites, 

ornamental sites, field-grown plant nurseries, compost piles, and potting soils. It is used 

2 
primarily to manage weeds (including golf course renovations requiring killing of existing 

turfgrass), nematodes, and pathogens prior to planting of the crops. 

Non-agricultural antimicrobial use sites for which dazomet is labeled include: 1) as a treatment 

during the production of pulp and paper; 2) as a material preservative treatment for paper 

coatings, non-food adhesives, epoxy flooring compounds, slurries, and high viscous suspensions; 

3) as a biocide treatment used during petroleum operations; 4) as a biocide treatment to 

recirculating cooling water systems; and 5) as a remedial wood treatment to utility poles (REDFS, 2008). It also appears to have uses on rights-of-way. 

USAGE 

Agricultural Use 

A review of available proprietary data did not yield information on the amount of dazomet used 

for agricultural uses. The only public data source which had information on agricultural use of 

dazomet was from the state of California which showed that approximately 800 lbs a.i. of 

dazomet was used on soils for plums in 2009, and approximately 600 lbs a.i. was used on soils 

for plums in 2010. In spite of a label for pre-plant use for strawberries and tomatoes, BEAD 

found no data on usage for these sites. 

Non-Agricultural Use 

In terms of non-agricultural use, information is available for dazomet use on golf courses in 2002 

(15,500 lbs. a.i.) and 2006 (approximately 6,000 lbs. a.i.), and by lawn care operators 

(approximately 3,500 lbs. a.i.) in 2006 (Kline & Co. 2002,2006). Additionally, according to the 

Nursery and Floriculture Summary of the USDA, approximately 15,000 pounds of dazomet was 

used as a soil fumigant in 2003 (USDA-NASS, 2004). Also, in 2010 in California, 55,511 

pounds of dazomet were used on rights-of-way; however, there was no information available on 

use of dazomet for rights-of-ways in other states (CDPR, 2010). 

PREVIOUS BEAD ASSESSMENTS FOR DAZOMET 

Most of the BEAD work on dazomet has been in the context of benefits assessments or impact 

assessments for other fumigants including methyl bromide and 1,3-D, for which dazomet could 

be an alternative. In that context, dazomet was found to have low benefits relative to other 

fumigants in many crops, due to inconsistent results, and less control of weeds than other 

fumigants. However, where the availability of other fumigants is restricted, dazomet could be an 

important alternative, along with the other MITC generators (Zinn and Smearman, 2007; 

Yourman and Smearman, 2007a; Faulkner and Yourman, 2007; Y ourman and Smearman, 

2007b). 

3 
A report on use of dazomet in California indicates primary use sites in landscape and rights of 

way (Carter, 2008). This suggests some degree of benefits of dazomet for those uses, probably 

because of ease of application in the granular fonnat. 

BIOLOGICAL ASPECTS RELEVANT TO DAZOMET 

Dazomet is applied as a dry granule and incorporated into the soil or applied to the soil surface 

and watered into the soil to activate it (RED-FS, 2008). The ease of application and efficacy for 

many use sites suggest a relatively high benefit, especially with the need for alternatives after the 

phase-out of methyl bromide. Under moderate soil temperatures and moisture, dazomet has been 

successful in replacing such fonner methyl bromide-uses as turfgrass removal for golf courses 

undergoing renovation (e.g., Brecke et al., 2005). Dazomet has been used in forest seedling 

nurseries, especially in western and northern states. It generally has not provided comparable 

weed control compared to the long-time standard methyl bromide and its use has been found in 

some cases to a reduction in seedling grade (Fraedrich and Dwinell, 2003). This is possibly a 

consequence of a low vapor pressure of the MITC component, which reduces the fumigant's 

dispersal within the soil especially under extreme soil moisture and temperatures (where methyl 

bromide might have been effective). 

REFERENCES 

Brecke, B. J., Unruh, J. B., and Stephenson, D. 0.2005. Dazomet blended with rootzone mix for 

fumigation. International Turfgrass Society Research Journal 10:1176-1178. 

http://archive.lib.msu.edultic/its/articles/2005jou 11 76.pdf 

Carter, J. 2008. Usage Report in Support of Registration Review for the fumigant Dazomet 

(035602), BEAD, January 15,2008. 

CDPR (California Department of Pesticide Regulation). Summary of Pesticide Use Report Data, 

20 1 D-Indexed by Chemical. http://www.cdpr.ca.gov/docs/pur/pur10rep/chmrptlO.pdf 

Faulkner, J. and Yourman, L.2007. Assessment of the Benefits Soil Fumigants (Methyl Bromide, 

Chloropicrin, Metam-Sodium, Dazomet) Used by Forest Tree Seedling Nurseries, BEAD, April 

20,2007. 

Fraedrich, S. W. and Dwinell, L. D. 200J. An evaluation of dazomet incorporation methods on 

soilborne organisms and pine seedling production in southern nurseries. Southern Journal of 

Applied Forestry 27:41-51. http://www.srs.fs.usda.gov/pubs/ja/ja fraedrich003.pdf 

Kline & Co., 2002, 2006 

RED-FS. 2008. Registration Eligibility Decision Fact Sheet: Dazomet. U.S. Environmental 

Protection Agency Office of Pesticide Programs. July 10,2008. 

http://www .epa. gov /oppsrrd 1 /REDs/factsheets/ dazomet -fs. pdf 

4 
USDA-NASS. 2004. Agricultural Chemical Usage 2003 Nursery and Floriculture Summary, 

September 2004. 

http://usda.mannlib.comell.edulMannU sdaiviewDocumentlnfo.do?documentlD= 1 00 1 

US EPA. 2009. Amended Reregistration Eligibility Decision for Dazomet. 

Yourman, L. and Smearman,S. 2007a. Assessment of the Benefits of Soil Fumigation with Methyl 

Bromide, Chloropicrin, Dazomet, and Metam Sodium for Use in Raspberry Nurseries, Fruit and 

Nut Deciduous Tree Nurseries, and Rose Bush Nurseries in California, BEAD, April 20, 2007. 

Yourman, L. and Smearman,S. 2007b. Chloropicrin, Methyl Bromide, Metam-sodium and 

Dazomet Use in Strawberry Nursery Runner Production, BEAD, April 19, 2007. 

Zinn, N. and Smearman, S. 2007. Assessment of the Benefits of Soil Fumigation with 

Chloropicrin, Methyl Bromide, Metam Sodium and Dazomet in Ornamental Production, BEAD, 

April 20, 2007 

5