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U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Pesticide Management & Coordination

Pesticide-Use Risk Assessments and Worksheets

Risk Assessments

Forest managers frequently make decisions regarding the use of pesticides on forest lands. These decisions must be based not only on the effectiveness of these tools, but also on an understanding of the risks associated with their use. For the pesticides commonly used by the Forest Service in its management activities, Human Health and Ecological Risk Assessments (HERAs) are prepared.

Worker reading label prior to field work

Worker reading label prior to field work. Photo by USDA Forest Service - Region 8.

In these documents, the process of risk assessment is used to quantitatively evaluate the probability (i.e. risk) that a pesticide use might pose harm to humans or other species in the environment. It is the same assessment process used for regulation of allowable residues of pesticides in food, as well as safety evaluations of medicines, cosmetics, and other chemicals. The Forest Service incorporates relevant information from the HERA into environmental assessment documents prepared for pesticide projects, and are used to guide decision-making and to disclose to the public potential environmental effects.

Risk is defined as the likelihood that an effect (injury, disease, death or environmental damage) may result from a specific set of circumstances. It can be expressed in quantitative or qualitative terms. While all human activities carry some degree of risk, some risks are known with a relatively high degree of accuracy, because data have been collected on the historical occurrence of related problems (i.e. lung cancer caused by smoking, auto accidents caused by alcohol impairment, and fatalities resulting from airplane travel). For several reasons, risks associated with activities including exposure to chemicals such as pesticides cannot be so readily determined. The process of risk assessment helps evaluate the risks resulting from these situations.

When evaluating risks from the use of pesticides proposed in a NEPA planning document, reliance on U.S. EPA’s pesticide registration process as the sole demonstration of safety is insufficient. The Forest Service and Bureau of Land Management were involved in court cases in the early 1980’s that specifically addressed this question (principally Save Our Ecosystems v. Clark, 747 F.2d 1240, 1248 (9th Circuit, 1984) and Southern Oregon Citizens v. Clark, 720 F. 2d 1475, 1480 (9th Cir. 1983)). These court decisions and others affirmed that although the Forest Service can use U.S. EPA toxicology data, it is still required to do an independent assessment of the safety of pesticides rather than relying on FIFRA registration alone. The Courts have also found that FIFRA does not require the same examination of impacts that the Forest Service is required to undertake under NEPA. Further, Forest Service assessments consider data collected from both published scientific literature and data submitted to U.S. EPA to support FIFRA product registration, whereas U.S. EPA utilizes the latter data only. The U.S. EPA also considers many forestry pesticide uses to be minor. Thus, the project-specific application rates, spectrum of target and non-target organisms, and specialized exposure scenarios evaluated by the Forest Service are frequently not evaluated by U.S. EPA in its generalized registration assessments.

Risk assessment documents and worksheets have been developed for a number of pesticides that are used by the Forest Service. Existing risk assessments may be used in lieu of a project-specific risk assessment.

For further detail of the Forest Service risk assessment process for pesticides and how it is used, please consult “Preparation of Environmental Documentation and Risk Assessments”.

Risk Assessment Worksheets

Risk assessment worksheets are a computational tool developed for the USDA Forest Service by Syracuse Environmental Research Associates, Inc. (SERA). These worksheets perform many of the calculations used in the Human Health Risk Assessments (HHRA) and Ecological Risk Assessments (ERA) prepared for many of the pesticides used by the Forest Service.

Worksheet Use

The basic idea of these worksheets is to isolate the computations from the discussions of the computations. The worksheets contain very little discussion and they are intended as a tool to make risk assessment calculations easier to understand and review. Pesticide Coordinators and other technical specialist familiar with HHRAs and ERAs can use these worksheets to develop risk values for the pesticide application rates and application scenarios specific to their particular pesticide project. The worksheets for the pesticides listed below, are presented in EXCEL format and can be downloaded for your use. The worksheets can be used to perform computer based project specific (site-specific) calculations that incorporate the characteristics of your project including chemical formulation, use rate, and site factors.

Documentation

Prior to using the worksheets, we recommend that you read the documentation provided for WorksheetMaker Version 6.01.16 and the accomanying errata notes provided by SERA Inc. The documentation explains the organization of the worksheets, computation specifications, and other technical information. The latest release of WorksheetMaker Version 6.01.16 and supporting documentation, including the User Guide, is contained within the WorksheetMaker 6.01.16 zip file. This version includes the corrections to the WSM database from July 2016. See the documentation for additional details.

Support

Please note that SERA Inc. do not provide technical support for this product through telephone inquiries. If you have any questions about the worksheets, please contact the appropriate Regional Pesticide Coordinator in your region. For the pesticides Isoben, MCH and Verbenone, the worksheets available are in an earlier Version 2,04b, but will perform the same computations.

Pesticide-Use Risk Assessment Documents and Worksheets:
HERBICIDES DOCUMENTATION/WORKSHEET
Aminocyclopyrachlor Aminocyclopyrachlor (1.8 MB PDF)
Aminocyclopyrachlor EPA Bibliography (320 KB PDF)
Worksheet (Attachment 1) (2.3 MB xlsm)
Worksheet (Attachment 2) (1.7 MB xlsm)
Aminopyralid Aminopyralid (1.38 MB PDF)
Worksheet (5.5 MB xls)
2,4-D 2,4-D (1.4 MB PDF)
Worksheet (Acid & Salt) (5.4 MB xls)
Worksheet (Esters) (4.6 MB xls)
Chlorsulfuron Chorsulfuron (941 KB PDF)
Worksheet (5 MB xls)
Clethodim Clethodim (2.5 MB PDF)
Worksheet (Single Application) (2.4 MB xlsm)
Worksheet (2 Applications) (2.4 MB xlsm)
Worksheet (4 Applications) (2.4 MB xlsm)
Worksheet (18 Applications) (2.4 MB xlsm)
Clopyralid Clopyralid (940 KB PDF)
Worksheet (5 MB xls)
Dicamba Dicamba (Vanquish) (1 MB PDF)
Worksheet (5 MB xls)
Endothall Endothall (1.28 MB PDF)
Worksheet (Aq K) (5.45 MB xls)
Worksheet (Aq Super K) (5.4 MB xls)
Worksheet (Liquid) (5.45 MB xls)
Worksheet (Granular) (5.4 MB xls)
Worksheet (Occup) (273 KB xls)
Fluazifop-P-Butyl Fluazifop-P-Butyl (2.7 MB PDF)
Worksheet (Single Application) (2.4 MB xlsm)
Worksheet (2 Applications) (2.4 MB xlsm)
Worksheet (3 Applications) (2.4 MB xlsm)
Fluridone Fluridone (1.1 MB PDF)
Worksheet (5 MB xls)
Fluroxypyr Fluroxypyr (1.4 MB PDF)
Worksheet (5.8 MB xls)
Glyphosate (Accord, Rodeo, Roundup, Roundup Pro) Glyphosate (1.84 MB PDF)
Glyphosate Appendices (1.3 MB PDF)
Worksheet (Backpack) (6 MB xls)
Worksheet (Ground) (6 MB xls)
Worksheet (Aerial) (6 MB xls)
Worksheet (Aquatic) (5.5 MB xls)
Worksheet (Interactions) (245 KB xls)
Hexachlorobenzene Worksheet (in Clopyralid) (4.8 MB xls)
Worksheet (in Picloram) (4.8 MB xls)
Hexazinone Hexazinone (1.3 MB PDF)
Worksheet (granular) (5 MB xls)
Worksheet (liquid) (5 MB xls)
Imazamox Imazamox (1.3 MB PDF)
Worksheet (Aquatic) (5.5 MB xls)
Worksheet (Terrestrial) (6 MB xls)
Imazapic Imazapic (602 KB PDF)
Worksheet (5 MB xls)
Imazapyr (Arsenal, Chopper, Stalker) Imazapyr (1.8 MB PDF)
Worksheet (Aquatic) (1.9 MB xlsm)
Worksheet (Terrestrial) (2.1 MB xlsm)
Isoxaben Isoxaben (2.8 MB PDF)
Worksheet (446 KB xls)
Metsulfuron Methyl (Escort) Metsulfuron Methyl (928 KB PDF)
Worksheet (5 MB xls)
Oryzalin Oryzalin (536 KB pdf)
Worksheet (2.3 MB xlsm)
Oxyfluorfen Oxyfluorfen (1.16 MB PDF)
Worksheet (5.6 MB xls)
Picloram Picloram (2.37 MB PDF)
Worksheet (5 MB xls)
Worksheet (Foliar Applications) (2.13 MB xlsm)
Worksheet (Hexachlorobenzene) (1.27 MB xlsm)
Sethoxydim (Poast) Sethoxydim (Poast) (3 MB PDF)
Worksheet (Poast) (379 KB xls)
Sulfometuron Methyl Sulfometuron Methyl (876 KB PDF)
Worksheet (5 MB xls)
Tebuthiuron Tebuthiuron (1.9 MB PDF)
Worksheet (Attachment 1) (2.3 MB xlsm)
Worksheet (Attachment 2) (2.2 MB xlsm)
Worksheet (Attachment 3) (2.2 MB xlsm)
Worksheet (Attachment 4) (2.2 MB xlsm)
Trifluralin Trifluralin (2.16 MB PDF)
Worksheet (Attachment 1) (2.1 MB xlsm)
FUNGICIDES DOCUMENTATION/WORKSHEET
Borax Borax (1.8 MB PDF)
Worksheet (cellu-treat) (1.7 MB xlsm)
Worksheet (liquid) (1.7 MB xlsm)
Worksheet (dry-stump) (1.7 MB xlsm)
Chlorothalonil Chlorothalonil (436 KB pdf)
Worksheet (2.3 MB xlsm)
Dazomet Dazomet (345 KB pdf)
Worksheet (1.9 MB xlsm)
Mancozeb Mancozeb (454 KB pdf)
Worksheet (2.3 MB xlsm)
INSECTICIDES DOCUMENTATION/WORKSHEET
Carbaryl Carbaryl (1.72 MB PDF)
Worksheet (bark beetle) (5 MB xls)
Worksheet (leaf beetle) (5 MB xls)
Chlopyrifos Chlopyrifos (346 KB pdf)
Worksheet (2.3 MB xlsm)
DDVP DDVP (Dichlorvos) (1.4 MB PDF)
Worksheet (248 KB xls)
Diflubenzuron Diflubenzuron (Dimilin) (1.15 MB PDF)
Worksheet (5 MB xls)
Dinotefuran Dinotefuran (1.63 MB PDF)
Worksheet (ABF 1) (5.8 MB xls)
Worksheet (ABF 2) (5.8 MB xls)
Worksheet (granular) (5.7 MB xls)
Worksheet (bark) (5.7 MB xls)
Worksheet (soil) (5.4 MB xls)
Worksheet (tree) (5 MB xls)
Worksheet (bees) (194 KB xls)
Emamectin Benzoate Emamectin Benzoate (1.4 MB PDF)
Worksheet (1 MB xlsm)
Gypchek Gypchek (414 KB PDF)
Imidacloprid Imidacloprid (3 MB PDF)
Imidacloprid Appendices (1.4 MB PDF)
Worksheet (tree-injection) (1.6 MB xlsm)
Worksheet (soil-injection) (2 MB xlsm)
Worksheet (bark-applications) (2.3 MB xlsm)
Worksheet (backpack-directed-foliar) (2.3 MB xlsm)
Lambda-Cyhalothrin Lambda-Cyhalothrin (1.54 MB PDF)
Worksheet (Chico) (6.05 MB xls)
Worksheet (Foresthill) (6.03 MB xls)
Malathion Malathion (1.93 MB PDF)
Worksheet (ULV) (5.19 MB xls)
Worksheet (EC) (5.18 MB xls)
Rotenone Rotenone (1.64 MB PDF)
Worksheet (5 MB xls)
Spinosad Spinosad (2.5 MB PDF)
Worksheet (one application) (2.4 MB xlsm)
Worksheet (two applications) (2.4 MB xlsm)
Tebufenozide (Mimic) Tebufenozide (Mimic) (884 KB PDF)
Worksheet (granular) (5 MB xls)
PHEROMONES DOCUMENTATION/WORKSHEET
Disparlure Disparlure (413 KB PDF)
Worksheet (167 KB xls)
Methylcyclohexene-1-one (MCH) Methylcyclohexene-1-one (MCH) (267 KB PDF)
Worksheet (154 KB xls)
Verbenone Verbenone (240 KB PDF)
Worksheet (157 KB xls)
OTHER RISK ASSESSMENTS/WORKSHEETS DOCUMENTATION/WORKSHEET
An Evaluation of Gleams-Driver for Estimating Concentrations of Pesticides in Surface Water An Evaluation of Gleams-Driver for Estimating Concentrations of Pesticides in Surface Water (851 KB PDF)
Aqueous Chlorine-Based Antimicrobial/Disinfectant Aqueous Chlorine-Based Antimicrobial/Disinfectant (999 KB PDF)
Chlorophacinone CHLOROPHACINONE (1.15 MB PDF)
Worksheet (2 MB xlsm)
Gypsy Moth Risk Comparison Gypsy Moth Risk Comparison (570 KB PDF)
Marker Dyes Marker Dyes (204 KB PDF)
Neurotoxicity, Immunotoxicity, and Endocrine Disruption with Specific Commentary on Glyphosate, Triclopyr, and Hexazinone Neurotoxicity, Immunotoxicity, and Endocrine Disruption with Specific Commentary on Glyphosate, Triclopyr, and Hexazinone (251 KB PDF)
Preparation of Environmental documentation and Risk Assessments Preparation of Environmental documentation and Risk Assessments (1.8 MB PDF)
Strychnine Strychnine (2.46 MB PDF)
Worksheet (5.83 MB xls)
Surfactants Effects on Glyphosate Toxicity Surfactants Effects on Glyphosate Toxicity (149 KB PDF)
Technical Comparison of EPA, BLM and Forest Service Pesticide Risk Assessments Technical Comparison of EPA, BLM and Forest Service Pesticide Risk Assessments (198 KB PDF)
Tussock Moth Biocontrol Toxicity Tussock Moth Biocontrol Toxicity (198 KB PDF)
Worker Exposure 2014 Worker Exposure 2014 (1.75 MB PDF)
Worker Exposure 2014 Appendices (771 KB PDF)
Worksheet (918 KB xlsm)