Page 1 of 22 **UNITED STA TES ENVIRONMENTA**  **L PROTECTION A GENCY** 

**WA SHINGTON, D.C. 20460**  **OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION** 

**MEMORANDUM (DRAFT)**  **Date :**  March 2 4 , 201 5 **SUBJECT:** Review of “Determination of Dermal and Inhalatio n Exposure to Workers during Backpack and Handgun Application of Liquid Sprays in Utilities Rights - of - Way” (AHE400) **PC Code: --**  **DP Barcode:** D 424153 **Decision No.: --**  **Registration No. :**  **-- Petition No.:**  **-- Regulatory Action:**  **-- Risk Assessment Type:**  **-- Case No.:**  -- **T XR No.:**  **-- CAS No.:**  **-- MRID No.:**  4 9472001 **40 CFR: --**  **FROM:** Matthew Crowley , Biologist

Chemistry

and Exposure Branch Health Effects Division **THROUGH:** David J. Miller, Chi ef

Chemistry

and Exposure Branch Health Effects Division **TO:** Richard Dumas

Pesticide Registration Division This memorandum presents EPA’s review of the anal ytical and field phase reports for AHE400 (AHETF, 2014) , an Agricultural Handler Exposure Task Force (AHETF) study monitoring dermal and inhalation exposure for workers making backpack or handgun application s of liquid sprays to utility

rights - of - way an d similar areas. The scenario monograph s ( Bruce, et al, 2014a and 2014b ) , which incorporate the monitoring data from AHE400 into single/composite dataset s and includes statistical analysis based on pre - defined benchmark accuracy ob j ective s , are reviewed under separate cover ( Crowley , 201 5 a and 201 5 b ). This study meet s EPA standards for occupational pesticide exposure monitoring and are considered acceptable and appropriate for use in occupational exposure assessments for backpack and handgun applicators .Page 2 of 22

**1. 0**  **Executive Summary** The Agricultural Handler Exposure Task Force (AHETF) monitored dermal and inhalation exposure for 21 workers using handgun sprayers and 19 workers using backpack sprayers while applying liquid spray pesticides to undesirable vegetation such as shrubs, vines, and trees in areas such as utility

rights - of - way (ROW) , parks, roadsides, and wildlife refuges across the eastern half of the United States. Importantl y, the pesticide solution was not prepared b y the monitored workers; thus, re sult s of monitoring did not include exposures during th e pesticide mixing process . Backpack applications in this study were conducted using a handwand attached to a low - volume tank worn on a worker’s back. While walking through the target area, the pesti cide solution is sprayed b y manually pressurizing the spray tank with a hand -pump attached to the backpack and squeezing the trigger on the wand. Additionall y, some of the workers using backpacks also performed “hack- and - squirt” applications (a direct/loc alized spray following a slice/cut to the base of a tree or bush). Handgun a

pplications in this study

were conducted with a handgun attached to a hose, which is in turn attached, through a mechanical pump, to a vehicle - mounted holding tank. The mechanical pump provides the pressure to spray the pesticide solution. The workers often sprayed the target vegetation from the vehicles, but at times had to drag the hose and walk in and around the target ed area s . Table 1 presents a high - level summary of all o f the exposure monitoring. **Table 1. AHE400 Summ ary**  **Equipment Site**  **State No.**  **Monitored Worker**  **- Days**  **Monitoring Year**

**(for each Worker -**  **day) Age**  **Range (years)**  Backpack ROW & Park PA 3 2012/ - 12/ - 13 2 9 - 53 NC 1 2011 33 ROW GA 1 2011 29

SC 1 2012 38 W ildlife Refuge & ROW FL 3 2011/ - 12/ - 12 26 - 48 ROW AR 3 2011/ - 12/ - 12 21 - 31 Pipeline terminal & ROW IN 2 2012/ - 13 24 - 34 Park & Drainage ditch MI 2 2012/ - 13 33 - 37 ROW TX 3 2011/ - 12/ - 12 27 - 29

Handgun ROW PA 2 2012 54 - 68 WV 1 2012 49 NC 2 2011/ - 13 34 - 47 TN 1 2012 48 FL 3 2011/ - 13/ - 13 27 - 54 MN 2 2013 / - 13 20 - 48 Fence line & ROW LA 3 2012 / - 12/ - 12 20 - 48 Pipeline terminal & ROW IN 3 2012/ - 12/ - 13 19 - 39 Roadsides MI 1 2012 45 Drainage ditch & ROW TX 3 2011/ - 11/ - 12 25 - 58 Note: all study subjects were male.Page 3 of 22

Monitored on actual days of work, backpack applicator s handled from 0.03 to 9 .65 lbs of active ingredient , spraying 4 .5 to 64.5 gallons of solution in 2 to 10.7 hours , covering (when recorded) less than 1 to approximately 6 acres . Handgun applicators handled from 0.077 to 45.95 lbs of active ingredient , spraying 71 to 2900 gallons of solution in 3.3 to 11.4 hours , covering less than 1 to approximately

20 acres . Applicators wore long - sleeved shirts, pants, shoes/socks and chemical - res istant gloves, with a few donning protective leggings and eye protection. No applicator wore a respirator. Dermal exposure was measured using hand washes , face/neck wipes , and whole body dosimeters (100% cotton union suits) for the remainder of the body (torso, arms, and legs). Inhalation exposure was measured using personal air sampling pumps and OSHA Versatile Samplers (OVS) mounted on the shirt collar. All studies followed the applicable and most up - to - date AHETF standard operating procedures (SOPs) and the ir corresponding protocols with deviations appropriatel y recorded . No protocol deviation is considered to have compromised the overall research. Anal ytical f ield and laboratory recovery

results were acceptable, generally averaging between 70 and 1 20% recovery , with coefficients of variation generall y lower than 25% . All field samples were appropriately adjusted for the corresponding recovery adjustment factors. Total dermal exposure 1 , calculated b y summing the results for inner dosimeters, hand washes and face/neck wipes, as well as dermal exposure normalized to body weight and also normalized to the amount of active ingredient handled are summarized in Table 2 below. **Table 2. Derm al Exposure Summary**  **Equipment Statistic**  **1 Total Exposure**  **(μg) N**  **orm alized**  **by Body**  **Weight (μg/kg BW)**  **Norm alized by**  **Am ount ai**  **Handled (**  **μg/lb ai) 2**  Backpack Minimum 34 0. 4 8 675

Maximum 7 52,379 8, 360 241,923 Mean 7 3,414 8 55 31,273 Handgun Minimum 80 0.88 26

Maximum 112,258 1,467 12,123 Mean 12,431 135 1,868 1 Means are simple averages (i.e., sum of values ÷ n) 2 Though other exposure metrics are shown in this table, exposure normalized to the amount of active ingredient handled is typically the format used by EPA as an input in standard handler exposure calculatio ns. Total inhalation exposure, calculated2 assuming a breathing rate of 16.7 L/min 3 , as well as inhalation exposure normalized to body weight and also normalized to amount of active ingredient handled are summarized in Table 3 below. 1 All dermal exposure values reflect a 2X adjustment on hand rinse and face/neck wipe me asurements accounting for assumed 50% residue collection method efficiency (see Section 3.3). Non - adjusted values are available in associated review spreadsheets. 2 Inhalation exposure (μg) = Residue collected * [Breathing rate (L/min) ÷ Pum p rate (L/min) ] . Pump rates generally were 2 L/min. Note: AHE400 presented the total active ingredient collected ( μg), not results adjusted for breathing rates as shown here. AHETF monograph submissions, reviewed separately, perform the calculation shown here. 3 NAFTA, 1998. Rate of 16.7 L/min represents light activity .Page 4 of 22 **T able 3**  **. Inhalatio**  **n Exposure Summary**  **Equipment Statistic**  **Total Exposure (μg)**  **Norm alized**  **by Body Weight** 

**(μg/kg BW) Norm**  **alized by Am**  **ount ai Handled**  **( μg/lb ai)**  Backpack Minimum 0.54 0.007 1.74

Maximum 567 7 112 Mean 100 1.22 35 Handgun Minimum 0.24 0.003 0.18

Maximum 670 8.28 35 M e an 88 1.09 7 Note: Means are simple averages (i.e., sum of values ÷ n) **2.0 Summary**  **of Field Stud y Characteristics**  This section provides summary characteristics for AHE400 . While a summary is provided, the submitted AHE400 report should be consulted for more specific details (applicable sections, tables, and/or page numbers are provided). **2.1 Administrative**  **Summary** AHE400 w as sponsored by the AHETF and adequately followed both the protocol and scenario construction plan (AHETF, 2010 a) , the AHETF Governing Document (AHETF, 2008 and 20 10b ) , and applicable AHETF SOPs . The study was conducted in compliance with Good L aboratory Practice Standards (GLPS) ( 40 CFR § 160 ) and met the standards in EPA Test Guidelines Series 875

– Occupational and Res idential Exposure (875.1100

– dermal exposure; 875.1300

– inhalation exposure). Deviations from GLPS are noted in AHE400 pages 3 - 4

– none are considered to have substantially

impacted the study

conduct or results. Signed copies of acceptable Quality Assurance and Data Confidentiality statements were provided. P rotocol amendments included : adding additional sources for recruitment ; allowance for additional clothing such as rubber boots, leggings, and headgear ; allowance for sites that are not strictly ri ghts - of - way but are similar in terms of vegetation and terrain and would be subject to similar pesticide applications ; increases to field fortification levels ; anal ytical method specifications ; and relaxing the “different employer” requirement. The amendm ents are all considered reasonable accommodations in order to carry out the study

and were appropriately documented. P rotocol deviations included : use of analy tical methods that were validated but had yet to be specified in the protocol ; failure to meet monitoring time and load thresholds ; potential lack of sampling test substance lots ; failure to perform a hand wash at a break ; use of non - AHETF provided gloves ; failure to notify potential employers of an introductory letter and phone call ; air sampling pump issues ; and a change to a principal analy tical investigator. None are considered to have negativel y impacted the study conduct or results.Page 5 of 22

For a more detailed summary of amendments and deviations, see Section 4.0 below and refer to AHE400 pages 11 - 14 as well as Appendix A (pages 454 - 538). **2.2 Test Materials**  Four potential surrogate active ingredients , all herbicides, were specifi ed in the protocol: gl yphosate, fosamine, 2,4 - D, and imaza py r. Backpack applications utilized 3 of 4 of the surrogates, each one sprayingeither gl yphosate, fosamine, or imaz a py r. Handgun applications utilized all four surrogate herbicide s, each one spraying either gl yphosate, fosamine, 2,4 - D, and imaz a py r . Per GLP, AHETF anal yz ed the test substances for purity . Certificat es of Analysis, which formally document analysis of the test substances, are provided in AHE400 Appendix F pages 1400 - 1430. AHETF determined that anal ys is of “Pre - Mix” products were suspect due to homogeneity

concerns and would instead, where applicable, use the label - specified active ingredient concentrations to calculate amount of active ingredient handled. Additionally , in some cases a sample of the product used was unattainable for anal ys is , so the nominal concentration listed by

the manufacturer on the product was used. AHE400 pages 65 - 68 and Table B - 2 on pages 92 - 93 provides more specific details on the products used and methodologies for calculating amount of active ingredient handled . This is also described more in Section 2.7 below . **2.3 Sample Size**  **, Monitored Workers, and Locations**  According to the Backpack and Handgun ROW Scenario Construction Plan (AHETF, 2010 a) and the AHETF Governing Document (AHETF, 2008 and 2010 b ) , a “ 7 x 3 ” configuration was deemed a reasonable approach for the se scenarios . That is, for each of the two scenario s , a total of 2 1 “monitoring units” (MU), obtained b y monitoring exposure from 7 spatially distinct study locations across the eastern U.S., each with 3 workers per location would be likely to satisfy pre defined accur acy benchmarks. Ultimately , 21 separate workers were monitored conducting handgun applications and 19 were monitored conducting backpack applications. The AHETF decided to terminate the backpack monitoring due to logistical difficulties and because they believed the resulting dataset would be adequate to meet scenario benchmarks. Discussion of the sampling design and related issues is covered under a separate review ( Crowley , 2015 a and 2015b ) . Monitoring locations we re all places where undesirable veget ation such as shrubs, vines, or bushes were meant to be controlled. Most of the monitoring was in utility rights - of - ways, such as areas through which electric transmission and distribution lines or pipelines run . These are areas where controlling vegetation is important so as to not only provide easy access to utility personnel and vehicles, but also because the vegetation can damage utility distribution equipment. Other monitoring areas included parks, drainage ditches, wildlife refuges , fence lines, an d roadsides where these types of pesticide applications are also conducted . While these are not rights - of

- way , both the purpose of the application (i.e., controlling undesirablePage 6 of 22

vegetation) and location characteristics such as terrain and vegetation ty pe were s imilar to the right - of - way locations that constituted the bulk of the monitoring. Table 4 below provides some more detailed characteristics of the workers and locations. The AHE400 study

report provides additional backpack applicator details in Tab le BP - 3 on pages 94 - 9 7 and handgun applicator details in Table HG - 3 on pages 284 - 287. **Table 4. Worker and Location Summary Equipment**  **Age**

**Range (years)**  **Gender Weight** 

**(lb )**  **Work Experience**  **(years) Site/Target**  **State Monitoring**  **Years** Backpack 21 - 53 All male 1 37 -

351 < 1 to 15 Distribution line ROW PA/SC/NC/AR/IN 2011 - 2013 Transmission line ROW PA/GA/FL/AR/TX 2011 - 2013 Wildlife refuge FL 2011 Pipeline ROW IN 2012 Park PA/MI 2012 - 2013 Drainage ditch MI 2013

Handgun 19

–

68 All male 12 7 -

251 < 1 to 34 Distribution line ROW NC/TN/LA/IN/MN/

TX 2011 - 2013 Transmission line ROW PA/WV/NC/FL/LA/ TX 2011 - 2013 Dist. and Trans. line ROW PA 2012 Drainage ditch TX 2011 Roadsides MI 2012 Fence line LA 2012 Pipeline terminal IN 2013 **2.4 Environmental Conditions**  Temperature (including heat index), humidity, wind speed and direction, cloud cover, and rainfall were all reported. The maximum reported temperature was 93 ° F ( Handgun application , TX, 2011 and Backpack application , AR, 2012 ) and the lowest reported temperature was 4 5 ° F ( Handgun application, WV, 2012 ). Rain impacted some of the monitoring. For two handgun applications, monitoring was halted during rain and the applicators took shelter and resumed applications after the rain stopped. Additionally , for each a backpack and handgun application , rain halted monitoring , but in each case in terms of time, amount applied, etc. monitoring was sufficiently

complete when halted . Maximum reported wind speed wa s approximately 20 miles per hour. In a few instances monitoring was a ffected or halted because the ambient temperature exceed ed the pre - defined threshold of concern for potential heat - related injury : one backpack application in West Virginia in 2012 (he at index = 106 ° F ) and two handgun applications (both in Texas, heat indices of 105 ° F in 2011 and 110 ° F in 2012). However in all cases in terms of time, amount applied, etc. monitoring was sufficientl y complete by the time the application was halted.Page 7 of 22

For more details on environmental conditions see the AHE400 report tables BP - 7 (pages 106 - 109 ) and HG - 7 (pages 296 - 299 ). **2.5 Clothing and Personal Protective Equipment (PPE)**  Per the stated goals of the AHETF, monitoring of backpack and handgun applications to undesirable vegetation in rights - of - way or similar areas was conducted to represent exposure for workers wearing long - sleeve shirts, pants, shoes/socks, chemical - resistant gloves and no respiratory

protection. While this was largel y the case , b ecause of the nature of the terrain and environment nearly

all workers wore (company- required) hard hats and some wore additional leg coverings ( 7 backpack applicators, 2 handgun applicators ) to protect from thorns or snakes. So long as the work clothing met the s tandards of the EPA Worker Protection Standard (WPS), monitoring was conducted with the clothing worn by the worker on the scheduled monitoring day . In three instances, the AHETF supplied workers with replacement shirts or pants prior to study initiation. P er protocol, new chemical - resistant gloves were supplied by the AHETF to all workers at the beginning of the day

and were available throughout the day according to WPS requirements . In one instance a worker (backpack applicator A27) preferred to wear his own chemical - resistant gloves

– this was noted as a protocol deviation . Additionally, many workers, either due to company policy

or worker preference or required by the pesticide label, wore protective eyewear . In these cases, the exposure measurement s were adjusted (according to AHETF SOP 9.K) to extrapolate deposited residue to those portions of the face/head covered by the protective eye wear. More specific details on work clothing and PPE can be found in the AHE400 study report in Tables BP - 4 and B P - 5 on pages 98 - 101 and Tables HG - 4 and HG - 5 on pages 288 - 291 . **2.6 Application**  **Equipment and Methods** For these studies, as indicated above, onl y application with either a backpack or handgun was monitored

– monitoring was not conducted for those workers resp onsible for mixing and loading the pesticide. For backpack applications, the worker used a handheld wand/hose/nozzle apparatus attached to a 3 to 4 gallon spray

tank mounted to their backs with shoulder straps. The spray tank solution was pressurized m anually using a lever. The spray nozzle ty picall y had a dual set - up where workers could switch between a straight stream or broad/fan stream. In three instances, in addition to the standard backpack applications, workers also conducted “hack- and - squirt” applications, also known as “frill” applications. For these, the trunk of a tree or bush is cut with a knife or machete, and spray solution applied with a small squirt bottle. For handgun applications, the worker sprayed with a wand/hose/nozzle apparatus attached to vehicle - mounted mechanical pressurizing pump and large spray tank. Vehicle ty

pes varied including all - terrain vehicles (ATVs), trucks and tractors. Workers sprayed the target vegetationPage 8 of 22

from the vehicles, but also at times got off the vehicl e dragging the hose behind them while walking through the area. Spray pressures varied, with most less than 100 pounds per square inch (psi), though some others used higher -pressure rigs (e.g., 800 psi) that can spray up to 30 feet. More details on app lication equipment and methods can be found in the AHE400 study report for backpack applications on p age 70 - 71 and Table BP - 6 on pages 102 - 105 and for handgun applications on page 259 and Table HG - 6 on pages 292 - 295. **2.7 Application**  **Rates** According to th e Backpack and Handgun ROW Scenario Construction Plan (AHETF, 2010 a) and the AHETF Governing Document (AHETF, 2008 and 2010b ), the total amount of active ingredient applied should be diversified across the scenario and within each study location . For ba ckpack applications, small volumes of liquid concentrate products (< 1 gallon up to 1 5 gallons) were mixed with water ( 7.5 to 4 00 gallons) according to label specified dilutions in a tank from which workers would load the spray into their backpack. Overal l workers sprayed 4.5 to 64.5 gallons of solution in 2 to 11 hours . In two cases (MUs A27 and A16) ready- to - use products (i.e., packaged as diluted solutions) were used so the amount of product in the spray is the same as the amount of spray prepared. Also, amounts handled reflect the “hack- and - squirt” applications conducted by three workers (MUs A1, A2, and A23) in addition to their backpack applications. Using the product concentration

– determined either b y purity anal ys is or labeled concentration

– with the known dilution and amount sprayed, the amount of active ingredient handled can be determined. B ackpack applicators handled from 0.03 to 9.65 lbs of active ingredient . Table 5 below provides more detail on backpack application rates. The subm itted AHE400 study report should also be referenced on page 71 and Tables BP - 6 (pages 102 - 105) and BP - 13 (page 250). **Table 5**  **. Backpack**  **Application Information MU**  **ID Site**  **Active Ingredient**  **(ai) Product** 

**Conc. (lb ai /**  **gal) Am** **t Product**  **in Spray**  **(gal) a**  **Am t** 

**Spray Prepared**  **(gal) Am** **t**

**Spray Applied**  **(gal) Loads**  **Sprayed (#)**  **Area Treated**  **(acres) Tim**  **e**

**(hr) AaiH**  **(lb) b**  A27 **c,d** Distribution Gl yphosate 0.32 5 5 4.5 2 Not recorded 3.5 1.44 A33 **d** Transmission Gl yphosate 2.67 9.5 160 28.5 10 5.25 9 4.49 A34 **d** Park Gl yphosate 3 2 100 13.5 4 3.5 2 0.81 A8 Distribution Fosamine 4.3 5.5 275 12.25 4 4 4 2.11 **f** A10 Transmission Gl yphosate 4.28 14 400 64.5 17 6 6.4 9.65 A20 **d** Distribution Imazapyr 4.19 0.5 210 48 12 0.75 5.1 0.48 A11 Wildlife

Refuge Imazapyr 0.45 1.5 300 22.5 9 3.3 8.2 0.051 A12 Transmission Gl yphosate 4.13 1.35 50 16.5 6 5 5 1.9 A13 Transmission Gl yphosate 4.13 1.35 50 20 7 5 5 2.27Page 9 of 22 **Table 5**  **. Backpack**  **Application Information MU**  **ID Site**  **Active Ingredient**  **(ai) Product** 

**Conc. (lb ai /**  **gal) Am** **t Product**  **in Spray**  **(gal) a**  **Am t** 

**Spray Prepared**  **(gal) Am** **t**

**Spray Applied**  **(gal) Loads**  **Sprayed (#)**  **Area Treated**  **(acres) Tim**  **e**

**(hr) AaiH**  **(lb) b**  A1 **d,e** Distribution Gl yphosate 2.67 11 151 33.25 10 2 10.7 6.65 A23 **e** Distribution Gl yphosate 3.9 8 160 14.5 5 0.45 6 3.11 A24 Transmission Imazapyr 2.04 1.25 225 33 10 Not recorded 4.3 0.37 A16 **c,d** Pipeline Gl yphosate 0.32 30 30 15.875 6 3.25 10.2 5.08 A38 **d** Distribution Gl yphosate 2.07 1.92 32 14.75 5 0.75 8.8 1.83 A31 Park Gl yphosate 3.02 0.4 16.5 16.5 6 0.6 6.3 1.13 A40 Drain age

Ditch Gl yphosate 4.07 0.15 7.5 7.5 7 0.9 7.8 0.62 A2 **d,e** Transmission Gl yphosate 2.67 15 200 16.5 7 0.75 7.5 3.62 A4 Transmission Imazapyr 1.98 0.28 300 16 6 2 6.1 0.03 A25 Transmission Gl yphosate 4 10 221 19.5 7 1.6 3.6 3.51 a Amount of product inc ludes any removal of small amounts used for purity analysis. **b** Amount active ingredient can be approximated by the calculation: product concentration (lb ai/gal product) *amount of product in spray mixture (gal prod) * [amount of spray mixture applied (g allons) ÷ amount of spray mixture prepared (gallons)]. Slight differences with the reported value are due to AHETF calculating and summing the amount ai handled for each load. c Product was a ready- to - use solution, so gallons of product in spray mixture and gallons of spray mixture prepared are the same. **d** Product was unavailable for sampling or was a “Premix” product

– thus, concentration on label was used for calculation purposes. **e** Worker also made “hack- and - squirt” applications. **f** Reflects the addition of a total (across 4 backpack loads) of 0.25 gallons (1 lb ai) of the product to the mixture. For handgun applications, small volumes of liquid concentrate products (< 1 gallon up to 12 gallons) were mixed with large volumes of water (~ 100 to 3100 gall ons) according to label specified dilutions. Workers then sprayed from 80 to 2900 gallons in about 3 to 11 hours. Using the product concentration

– determined either b y purity analysis or labeled concentration

– with the known dilution and amount sprayed , the amount of active ingredient handled can be determined. Handgun applicators handled from 0.077 to 45.95 lbs of active ingredient. Table 6 below provides more detail on backpack application rates. The submitted AHE400 study report should also be re ferenced for handgun applications on pages 259 - 260 and Tables HG - 6 (on pages 292 - 295) and HG - 13 (page 449). **Table 6**  **. Handgun Application Information MU**  **ID Site**  **Active**

**Ingredient (ai)**  **Product**

**Conc. (lb ai /**  **gal) Am** **t Product**  **in Spray**  **(gal) a**  **Am t** 

**Spray Prep**  **ared (gal)**  **Am t** 

**Spray Applied**  **(gal) Loads**  **Sprayed (#)**  **Area Treated**  **(acres) Tim**  **e**

**(hr) A**  **aiH (lb)**  **b** A28 **c** Trans. + Dist. ROW Gl yphosate 4 5 500 485 1 Not recorded 6.8 19.4 A29 **c** Trans. ROW Gl yphosate 2.67 6 600 580 3 6.09 6.7 15.49 A30 Trans. ROW Gl yphosate 4. 02 5 600 400 2 3 6.6 13.19 A9 Dist. ROW Fosamine 4.3 5.5 275 188 1 Not recorded 4.8 16.17 A19 Dist. ROW Imazapyr 2.13 0.75 900 700 3 4.7 8 1.24 A39 Trans. ROW Imazapyr 3.88 0.31 260 260 1 6.2 5.5 1.21 A6 Trans. ROW Imazapyr 1.88 2 250 190 3 40 8.4 2.89 A7 Trans. ROW Gl yphosate 4.27 2.7 295 86.5 2 52 9.7 3.54 A36 Trans. ROW Imazapyr 2.06 1.5 200 190 2 9.7 5.9 3.09 A14 Fence Line Imazapyr 1.96 0.46 185 144 4 0.36 7.1 0.71Page 10 of 22 **Table 6**  **. Handgun Application Information MU**  **ID Site**  **Active**

**Ingredient (ai)**  **Product**

**Conc. (lb ai /**  **gal) Am** **t Product**  **in Spray**  **(gal) a**  **Am t** 

**Spray Prep**  **ared (gal)**  **Am t** 

**Spray Applied**  **(gal) Loads**  **Sprayed (#)**  **Area Treated**  **(acres) Tim**  **e**

**(hr) A**  **aiH (lb)**  **b** A15 Trans. ROW Gl yphosate 4.18 d 6 755 671 13 Not recorded 6.4 21.73 A17 Dist. ROW Gl yphosate 4.23 6.3 315 225 2 3 5.2 19.04 A21 Dist. ROW 2,4 - D 2.51 1 200 200 4 1.2 6.6 2.51 A22 Dist. ROW 2,4 - D 3.76 2.125 635 635 3 2.2 7.4 7.99 A35 Pipeline Terminal 2,4 - D 2.32 3.9 107.5 104.5 7 1.5 8.1 8.87 A26 Roadsides Gl yphosate 4.11 12 3100 2 900 2 Not recorded 10.4 45.95 A32 Dist. ROW Fosamine 3.99 3.5 350 338 6 6.7 8.6 13.49 A37 Dist. ROW Imazapyr 2.06 0.13 275 80 4 Not recorded 11.4 0.077 A3 Trans. ROW Imazapyr 1.98 0.26 300 281 1 3 6 0.52 A5 Drainage

Ditch Gl yphosate 4.10 2.6 140 81 **e** 2 1 3.3 6.84 A18 Dist. ROW Gl yphosate 4.24 11 1000 900 2 17 6.9 41.98 a Amount of product includes any removal of small amounts used for purity analysis or for backpack applications . **b** Amount active ingredient can be approximated by the calculation: produ ct concentration (lb ai/gal product) *amount of product in spray mixture (gal prod) * [amount of spray mixture applied (gallons) ÷ amount of spray mixture prepared (gallons)]. Slight differences with the reported value are due to AHETF calculating and summing the amount ai handled for each load. c Product was unavailable for sampling or was a “Premix” product

– thus, concentration on label used for calculation purposes. **d** Represents the average of two product concentrations: 4.16 and 4.19 lb ai/gallon. **e** AHE400 incorrectly reports this as 71 gallons . **2.8 Exposure Monitoring and Analytical Methods**  Per applicable AHETF SOPs, standard p assive dosimetry methods recognized by EPA as appropriate for worker exposure monitoring were utilized for all monitoring . N o biomonitoring samples were collected. Dermal exposure to the hands was measured using a hand rinse method administered at the end of the workday as well as at lunch , restroom breaks , or other instances where workers would otherwise wash their hands as outlined in AHETF SOP 8.B . Dermal exposure to the face/neck was measured using a wipe technique as outlined in AHETF SOP 8.C and extrapolated to non - wiped portions of the head according to AHETF SOP 9.K . Thus, for those workers who wore eye protection and/or hard hats, the extrapolation to the whole head renders the resulting measurement somewhat representative of face/neck/head exposure without that additional gear. Generall y, 1 - 2 face/neck wipe samples were collected for each worker then anal yz ed as a co mposite sample. Dermal exposure to the remainder of the body (torso, arms, and legs) was measured using whole body dosimeters (100% cotton union suits), sectioned into six pieces and analyzed separately according to AHETF SOP 8.A . All these measurements combine to reflect dermal exposure underneath a single layer of work clothing (long - sleeve shirt, pants, shoes/socks) and chemical resistant gloves. Inhalation exposure was measured using OVS tubes mounted on the worker’s collar and personal sampling pump s (set at 2 liters per minute) according to AHETF SOP 8.D . The concentrations measured represent the chemical available in each worker’s breathing zone. The submitted AHE400 study report outlines the passive dosimetry procedures in more details on pages 14 - 18.Page 11 of 22

V alidated analy

tical methods specific to each typ e of monitoring matrix (i.e., inner dosimeters, hand rinses, etc.) were used to extract residues . The anal ytical methods are outlined in the anal ytical reports :  2.4 - D

– AHE400 Appendix B, pages 539 - 647  Fosamine

– AHE400 Appendix C, pages 648 - 760  Gly phosate

– AHE400 Appendix D, pages 761 - 1176  Imazap yr – AHE400 Appendix E, pages 1177 - 1399 . Limits of quantification and detection (as defined in AHETF SOP 9.A) are presented in Table 7 below . **Table 7**  **. Analytical Limits (**  **μg /sample) for AHE**  **400 Monitoring**  **Matrix Limit of Detection**  **Limit of Quantification**

**2,4 -**  **D Fosam** **ine Glyphosate**  **Imazapyr 2,4**  **- D**  **Fosam ine**  **Glyphosate Imazapyr**  Inner Dosimeter 0.30 0.1701 0.139 0. 041 1.0 Socks 0.060 0.0285 0.011 0.0355 0.25 Hand Rinse 0.30 0.1278 0.179 0.167 1.0 OVS air sampler (per section) 0.0015 0.0008 0.0016 0.0005 0.005 Face/Neck Wipe 0.30 0.3123 0.143 0.317 1.0 **3.0 Results**  This section provides a discussion of quality ass urance and quality

control sampling and the actual field monitoring measurements of workers. **3.1 Quality Assurance**  All phases of each study were subject to appropriate quality assurance processes according to EPA’s GLPs which included an audit by the AHETF Q uality Assurance Unit (QAU) per AHETF SOPs (AHETF SOP Chapter 5 : A - K) . The inspected phases were: Protocol, Field Phase, Field Data, Draft Report, Analytical Data, Final Report, and Post - Audit Report. The study contains a signed quality

assurance compl iance statement as required b y G LP s. Protocol amendments or deviations were addressed appropriatel y under GLP guidance and are described further in Section 4.0. **3.2 Quality Control**  AHETF instituted various quality control measures to ensure proper field con duct including calibration of sprayers, preparation and handling of exposure measurement matrices, evaluation of test material, and field observations (AHETF SOP Chapter 10 : A - G) . Analy tical methods were validated appropriately ensuring that all exposure matrices could be measured for the surrogate active ingredients proposed. Anal ytical quality control measures for ensuring thePage 12 of 22

integrity of measurements captured in the research were also instituted according to AHETF SOP 9 .J . Exposure monitoring matrices (inner whole body dosimeters, hand washes, face/neck wipes, OVS tubes) were fortified with known amounts of active ingredient to assess their stability during field, transit, and storage conditions according to AHETF SOP 8.E . Laboratory control sampl es were also fortified at the level of quantification and at levels capturing the range of expected field exposures for each matrix. Generally , field fortification samples were collected in triplicate at each of 3 levels (high, middle, and low) on each sa mpling day. Travel fortifications were generally

conducted on each day

of sampling in duplicate onl y at the high fortification level. Untreated control samples

– included to determine if there are significant background sources or contamination during sample processing

– were generally conducted in duplicate on each day of sampling. The following sections provide results for all quality control sampling across all exposure measurement matrices for all chemicals used. The identified supplemental tables s hould be referenced for chemical - specific results. **3.2.1 Field and Laboratory**  **Control Samples**  As expected, most n on - fortified (blank) laboratory and field control samples contained no detectable residues . For field controls, detectable residues (imazap yr, fos amine, and gl yphosate) were infrequent and found mostly in OVS tubes . F or laboratory controls , imazapy

r was detected in a few inner dosimeter and OVS tubes. Detections in the OVS tube control samples are not surprising given the sensitivity of the method

– the L OD ≤ 0.0016 ug/sample, and many were close to that residue level. For other dosimeters, the detections were all lower than the lowest field fortification level tested. Inall cases, both the frequency and magnitude of these detections did not indicate systematic contamination ; thus, p er standard AHETF procedure , no correction was made to any field monitoring samples based on results of control samples . More detailed results can be found in AHE400: Appendix B (2,4 - D) Tables 7 - 11 on pages 578 - 58 2; Appendix C (Fosamine) Tables 7 - 11 on pages 689 - 694; Appendix D (Gly phosate) Tables 11 - 16 on pages 844 - 860; Appendix E (Imazapy r) Tables 11 - 1 6 on pages 1241 - 1252 . **3.2.2 Field**  **Fortification Recoveries**  **– Applicable to Both Backpack and Handgun**  **Exposure Monitori ng**  Field fortification sampling matrices are spiked with known amounts of chemical, then placed under similar conditions and duration as the actual sampling matrices used on the workers (including drawing air through OVS samplers) . The intent of these samples is to quantify potential residue losses due to the sampling methods used under actual field conditions. Additional samples are also fortified to assess degradation of the sample during transit from the field to the lab and during sample storage. Ho wever, p er AHETF protocol, these are only anal yz ed if anomalous field fortification recoveries indicate potential degradation during transport and sample storage . No storage or transport fortification samples were anal yz ed sincePage 13 of 22

field fortification result s did not indicate any problems related to excessive degradation of residues . Field fortifications are conducted at 3 levels to capture the expected range of results, with triplicate samples taken on each day at each fortification level 4 . Once anal yzed, the average recovery results (expressed as a percentage of known amount applied) are used as multipliers to adjust, or correct, all measured field samples to 100% . As the fortification samples are conducted at levels to capture the range of expected field sample results, adjustments are done using the average percent recovery for the fortification level closest to the measured field sample 5 . The mid -point between each fortification level is used as the threshold in determining the average recovery

percent age for use in adjusting the field sample. With some ex ceptions, field fortification averages for each fortification level and each monitoring matrix were in the range of 70 - 120% with coefficients of variation generall y less than 25% . A summary

of field fortification results for each matrix is provided below in Sections 3. 2 .3.1

– 3. 2 .3.4 .

**3.2.2.1 Inner**  **D osimeters**  **and Socks** Results for inner whole body dosimeter (WBD) and sock field fortification samples were acceptable, with average recoveries ranging from 7 0 % to 1 20 % and coefficients of variation less than 25% . Some aty pically high and low average recoveries (~ 9% of all inner dosimeter and sock fortifications) were observed (48 - 66% and 121 - 153%), mostly for gly phosate fortifications in sock dosimeters . How ever, except for one fortification with a CV=31% (which did not end up being applicable to any field sample) all other CVs for these atypical results were less than 25%. For more details on field fortification results for inner dosimeters and socks see AHE400 Table BP - 11 on pages 216 - 232 and Table HG - 11 on pages 413 - 430. A djustments based on results for each surrogate active ingredient at each fortification level were applied to field samples falling into the following ranges 6 . Specific adjustment factor s associated with each of these ranges can be found in AHE400 in Tables BP - 12 on pages 233 - 249 and HG 12 pages 431 - 448.

 Imazap yr

/Gly phosate/Fosamine o WBD  Before 2012: ≤ 52.5 μg , > 52.5 to ≤ 2,050 μg , and > 2,050 μg 4 In 2012 fortification levels for dermal dosimetry were increased to accommodate field samples that exceeded the highest fortification level. 5 Per AHETF standard procedure, if average recovery is > 120% the maximum (“downward”) adjustment value applied is 1.2. 6 During revie w, EPA identified minor errors in the values used for recovery adjustments for WBD for backpack applicators: MU A10

– a value of 1.00 was used instead of 0.784 for the upper l eg sample; MU A23

– a value of 1.00 was used instead of 0.997 for most of the WBD samples; MU A25

– a value of 1.00 was used instead of 0.997 for some of the WBD samples. EPA decided to note these corrections but, because of the insignificant effect on ov erall results, not require any changes or re - submissions.Page 14 of 22  After 2012: ≤ 252.5 μg , > 252.5 to ≤ 25,250 μg , and > 25,250 μg o Socks:  Before 2012: ≤ 5.5 μg , > 5.5 to ≤ 55 μg , and > 55 μg  After 2012: ≤ 50.5 μg , > 50.5 to ≤ 2,550 μg , and > 2,550 μg  2,4 - D o WBD : ≤ 252.5 μg , > 252.5 to ≤ 25,250 μg , and > 25,250 μg o Socks: ≤ 50.5 μg , > 50.5 to ≤ 2,550 μg , and > 2,550 μg **3.2.2.2 Face/Neck Wipes**  Results for face/neck wipe field fortification samples were acceptable, with average recoveries ranging from approximately 7 0 % to 1 20 % and coefficients of variation less than 25% . Very few (~ 6%) atypical recoveries (63 - 68% and 125 - 149%) were observed, all with CVs less than 25%. For more details on field fortification results for face/neck wipes see AHE400 Table BP - 11 on pages 216 - 232 and Table HG - 11 on pages 413 - 430. Adjustments based on results for each surrogate active ingredient at each fortification level were applied to field samples falling into the following ranges. Specific adjustment factors associated with each of these ranges can be found in AHE400 in Tables BP - 12 on pages 233 - 249 and HG 12 pages 431 - 448.

 Gly phosate/Fosamine/2,4 - D/Imazapy r o Before 2012: ≤ 52.5 μg , > 52.5 to ≤ 1,050 μg , and > 1,050 μg o After 2012: ≤ 52.5 μg , > 52.5 to ≤ 2, 5 50 μg , and > 2, 5 50 μg **3.2.2.3 Ha**  **nd Washes** Results for hand wash field fortification samples were acceptable, with average recoveries ranging from approximately 70% to 120% and coefficients of variation less than 25%. Very few (~ 5%) atypical recoveries (43 - 64% and 121 - 124%) were observ ed (mostly for gly phosate), all with CVs less than 25%. For more details on field fortification results for face/neck wipes see AHE400 Table BP - 11 on pages 216 - 232 and Table HG - 11 on pages 413 - 430. Adjustments based on results for each surrogate active ingredient at each fortification level were applied to field samples falling into the following ranges. Specific adjustment factors associated with each of these ranges can be found in AHE400 in Tables BP - 12 on pages 233 - 249 and HG 12 pages 431 - 448.

 Gly ph osate/Fosamine/2,4 - D/Imazapy r o Before 2 012: ≤ 52.5 μg , > 52.5 to ≤ 1,050 μg , and > 1,050 μg o After 2012: ≤ 252.5 μg , > 252.5 to ≤ 5,250 μg , and > 5,250 μg **3.2.2.4 OVS Air Samplers**  Results for OVS field fortification samples were acceptable, with average recoveries ranging from approximately

70% to 1 20% and coefficients of variation less than 25%. Very few (~ 5%)Page 15 of 22

aty pical recoveries (59% and 12 4 - 1 38 %) were observed (mostl y for gl yphosate) , all with CVs less than 25%. For more details on field fortification results for face/neck wipes see AHE400 Tabl e BP - 11 on pages 216 - 232 and Table HG - 11 on pages 413 - 430. Adjustments based on results for each surrogate active ingredient at each fortification level were applied to field samples falling into the following ranges. Specific adjustment factors associat ed with each of these ranges can be found in AHE400 in Tables BP - 12 on pages 233 - 249 and HG 12 pages 431 - 448.

 Gly phosate/Fosamine/2,4 - D/Imazapy r : ≤ 2.525 μg , > 2.525 to ≤ 252.5 μg , and > 252 μg **3.3 Field**  **Measurements** The following sections summarize the exposure monitoring results, conducted as described in Section 2.8. Exposure values reflect total exposure for workers across their monitoring periods, not normalized by

any exposure metric. All measurements were appropriately adjusted for field fortification recoveries (see Section 3.2.2) . F ace/neck wipe measurements were extrapolated to un - wiped portions of the face and head according to AHETF SOP 9.K. For samples below the LOQ or LOD, 1⁄2 LOQ or 1⁄2 L OD was used . Additionally , in order to account for potential residue collection method inefficiencies, EPA m ake s adjustments to hand and face/neck field study measurements as follows 7 :  if measured exposures from hands, face and neck contribute less than 20% as an average across all workers , no action is required ;  i f measured exposure contribution from hands and face/neck represents between 20% and 60% of total, the measurements shall be adjusted upward b y a factor of 2 , or submission of a validation study to support the residue collection method  i f measured exposure contribution from hands and face/neck represents is greater than 60%, a validation study demonstrating the efficiency of the residue collection methods is required . For handgun applicators, the contribution of hands and face/neck exposures averaged 30% while for backpack applicators, the contribution averaged 27%. Therefore the results for exposures to the hands and head and total dermal exposures outl ined in the following sections present the aforementioned additional 2x adjustment for hand and face/neck measurements. **3.3.1 Inner Dosimeters**  **and Socks** For backpack applicators, without field fortification adjustments, individual WBD sections ranged from < 0.3 (non - detectable)

– 259,830 μg. Out of a total of 120 inner dosimeter samples, 3 were below the LOQ and 1 below the LOD. Sock samples without field fortification

7 This approach wa s discussed and presented at a meeting of the Human Studies Revie w Board (June 2007). The terminology used to describe this are “method efficiency adjusted” (MEA) or “method efficiency corrected” (MEC). Previous AHETF submissions included these adjustments but they have indicated that they will no longer continue to do so. Thus these ad

justments are instead made by EPA .Page 16 of 22

adjustments ranged from 0.95

– 3,959 μg. No sock dosimeter sample was below the LOQ or LOD. AHE400 Tables BP - 14 and BP - 15 on pages 251 - 252 provide more details on these samples. A fter adjusting for fiel d fortification recoveries and summing the six separate body sections, the total dermal exposure underneath the long - sleeve shirt and pants ranged from 6

– 730,551 μg with an average of 66,760 μg. Sock dosimeters with field fortification adjustments ranged from 1

– 3,884 μg with an average of 679 μg. For handgun applicators, AHE400 presents results for WBD and sock samples without field fortification adjustments. Individual WBD sections ranged from < 1.0 (non - detectable)

– 49,165 μg. O ut of a total of 126 inner dosimeter samples, 1 was below the LOQ . Sock samples ranged from 0.25

– 6,117 μg. Only 1 sock dosimeter sample out of 21 was below the LOQ. AHE400 Tables HG - 14 and HG - 15 on pages 450 - 451 provide more details on these samples. A fter adjusting for field fortification recoveries and summing the six separate body sections, the total dermal exposure underneath the long - sleeve shirt and pants ranged from 44

– 98,905 μg with an average of 8,497 μg. Sock dosimeters ranged from 0.13

– 6,185 μg with an average of 548 μg . **3.3.2 Face/Neck Wipes**  For backpack applicators face/neck wipe samples ranged from < 0.3 (non - detectable)

– 549 μg without field fortification adjustments . Out of 19 face/neck wipe samples, 1 was below the LOQ. AHE400 Tabl e BP - 15 on page 252 provides more details on these samples. For handgun applicators these ranged from 1.6

– 2,160 μg without field fortification adjustments . No face/neck wipe sample was below the LOQ or LOD. AHE400 Table HG - 15 on pages 451 provides more details on these samples. Because some workers wore eye protection and because measurements cannot be easily conducted on hair, extrapolations from those portions of the face/neck that are wiped need to be made to portions of the head that are not measured. Specifics on these adjustment factors can be found in AHETF SOP 9.K . Additionally , as previously described, the measurements are further adjusted upward b y EPA by a factor of 2 to account for potential inefficiencies in residue co llection by

the wip e technique. For backpack applicators, after adjusting for field fortification recoveri es and extrapolating to non - wiped portions of the head described above, total head exposure ranged from 0. 8

– 943 μg with an average of 200 μg . Including the 2X adjustment by EPA for potential method collection inefficiencies, total head exposure ranged from 1.6

– 1,886 μg with an average of 399 μg . For handgun applicators, after adjusting for field fortification recoveries and extrapolating to non - wiped portions of th e head described above, total head exposure ranged from 3

– 4,347 μg with an average of 500 μg. Including the 2X adjustment by EPA for potential method collection inefficiencies, total head exposure ranged from 6

– 8,694 μg with an average of 999 μg. **3.3.3 Han**  **d Washes** Per protocol, hand washes were collected at the end of each work day and at points where workers would normally

wash their hands such as during restroom or lunch breaks. MostPage 17 of 22

workers had 2 hand wash samples taken; one handgun applicator had 4 ha nd washes and one backpack applicator had 5 hand washes. A few workers, despite having relatively long work days (i.e., 4 - 8 hours) did not take any breaks and thus only

had the 1 hand wash sample conducted at the end of their workday . The following table outlines the number of hand wash samples broken down b y the work duration. **Table 8**  **. Hand Wash Summary Work Duration (hours)**  **< 4 4**  **- 6**  **6 -**  **8 ≥ 8**  Backpack Percentage of Workers 16% 26% 32% 26%

# of Hand Washes 1 - 2 1 - 3 1 - 2 2 - 5 Handgun Percentage of Workers 5% 19% 43% 33%

# of Hand Washes 1 1 - 2 1 - 4 2 - 3 For backpack appl icators, individual hand wash samples ranged from 3.5

– 8,404 μg without field fortification adjustments . No hand wash sample was below the LOQ or LOD. AHE400 Table BP - 15 on page 252 provides more details on these samples. For handgun applicators, individual hand wash samples ranged from < 1.0

– 3,042 μg without field fortification adjustments . Out of a total of 43 hand wash samples, 1 was below the LOQ. AHE400 Table HG - 15 on page 451 provides more details on these samples. For backpack applicators, after adjusting for field fortification recoveri es and summing hand wash es for each worker , the total hand exposure ranged from 13

– 10,776 μg with an average of 2,788 μg. Including the 2X adjustment by EPA for potential method collection inefficiencies, total hand exposure ranged from 26

– 21,552 μg with an average of 5,575 μg. For handgun applicators, after adjusting for field fortification recoveries and summing each hand wash, the total hand exposure ranged from 4

– 4,473 μg with an average of 1,194 μg. Including the 2X adjustment by

EPA for potential method collection inefficiencies, total hand exposure ranged from 8

– 8,946 μg with an average of 2,387 μg. **3.3.4 OVS Air Samplers**  **/Inhalation Exposure** Front and back sections of the OVS tube were analyzed separatel y. Most back section samples were less than the LOD , with a few less than the LOQ . All front section samples had detected residues. Inhalation exposure results were invalidated for two backpack applicators due to sampling pump failure (MU A27) and lack of remaining sample for anal ysis (MU A1

– sample extract was used up from previous anal ys is with an improper anal ytical method) . For backpack applicators, OVS front sections ranged from 0.0466

– 59.66 μg without field fortification adjustments . AHE400 Table BP - 16 on page 253 has more details on these results. A ft er adjusting for field fortification recoveries, the total (front section + back section) collected active ingredient amounts ranged from 0. 07

– 67 μg with an average of 1 2 μg. For handgun applicators, OVS front sections ranged from 0.0219

– 77.79 μg with out field fortification adjustments . AHE400 Table HG - 16 page 452 has more details on these results. A fter adjusting for field fortification recoveries, the total (front section + back section) collected active ingredient amounts ranged from 0. 03

– 80 μg with an average of 11 μg.Page 18 of 22

The above described results for the amount of active ingredient collected by the air sampling units. The AHE400 report

– as it is mainly a presentation of field and analy tical results

– presents onl y total active ingredient co llected b y the air sampling units. Separate AHETF monograph submissions (under separate EPA reviews) present worker inhalation exposures applying an assumed breathing rate. T o calculate worker inhalation exposure s , the measured amounts are adjusted based on the pump flow rate (in liters per minute) and a ty pical worker’s breathing rate for this ty

pe of activity. For these studies a breathing rate of 16.7 liters per minute was used, representing light activities (NAFTA, 1998). The calculation is as follo ws:

Inhalation exposure = Adjusted residue (μg) * [Breathing rate (LPM) ÷ Pump flow rate (LPM)] For backpack applicators, worker exposures ranged from 0.54

– 567 μg with an average of 100 μg. For handgun applicators, worker exposures ranged from 0.24

– 670 μg with an average of 88 μg. **3.4 Exposure**  **Calculation s**  This section provides total exposures (expressed as mass active ingredient), as well as exposures normalized to (i.e., dividing b y) body weight and amount of active ingredient handled (AaiH). **3.4.1 Derm**  **al Exposures** Total dermal exposure, calculated b y summing the results for inner dosimeters, hand washes and face/neck wipes, are presented below as well as normalized to body weight and amount of active ingredient handled. Results are presented both with and without adjustments for potential inefficiencies of the hand wash and face/neck wipe methods (MEA = method efficiency adjustment). **Table 9**  **. Derm al Exposure Summary**  **Equipment Statistic**  **Total Exposure (μg)**  **Norm alized**  **by Body**  **Weight (μg/kg BW)**  **Norm alized by**  **Am ount ai**  **Handled (**  **μg/lb ai) ME**  **A Non**  **- ME**  **A ME**  **A Non**  **- ME**  **A ME**  **A Non**  **- ME**  **A** Backpack Minimum 34 20 0.48 0.28 675 400

Maximum 752,379 742,664 8,360 8,252 241,923 238,799 Mean 73,414 70,426 855 819 31,273 30,110 Handgun Minimum 80 66 1.06 0.88 26 17

Maximum 112,258 108,674 1515 1,467 12,123 11,365 Mean 12,431 10,738 156 135 1,868 1,654 Note: Means are simple averages (i.e., sum of values ÷ n) **3.4.2 Inhalation**  **Exposures** As shown in Section 3. 3 .4, inhalation exposure is calculated based on the chemical in air over the monitoring period, the pump flow rate, and the worker’s breathing rate. Results are presented below.Page 19 of 22 **Table 10**  **. Inhalation**  **Exposure Summary Equipment**  **Statistic Total Exposure**  **(μg) Norm**  **alized by**  **Body Weight**  **(μg/kg BW) Norm**  **alized by Am**  **ount ai Handled**  **( μg/lb ai)**  Backpack Minimum 0.54 0.007 1.74

Maximum 567 7 112 Mean 100 1.22 35 Handgun Minimum 0.24 0.003 0.18

Maximum 670 8.28 35 Mean 88 1.09 7 Note: Means are simple averages (i.e., sum of values ÷ n) **3.5 Field Observations**  Field researchers observed each worker and record ed their behavior throughout the work day . These can be found in the AHE400 report in Table BP - 9 on pages 112 - 174 and HG - 9 on pages 302 - 369. Much of the observations detailed routine application procedures (e.g., MU A27 @ 0815 : “ Sprayed a ~20 ft. section of high brush along side of road .”) . Other observations may potentially

provide clues as to determinants of exposure

– examples of these ty pes of ob servations include:

 Overhead spraying

– e.g., MU A33 @ 0902: “Spray s a birch tree (~5 ft. tall) on hillside, which requires overhead spraying. Large visible plume, moderate contact with A33” ;  Contact with treated foliage

– e.g., MU A10 @ 1102: “A10 obser ved walking directly into just sprayed foliage (below waist high)”;  Getting off truck to walk and spray target area (handgun)

– e.g., MU A22 @ 0918: “A22 down from truck, walking along ROW area, spraying into ROW.” EPA reviewed the field observations for potential clues as to determinants of exposure or potential reasons for high exposures. Though difficult to quantify in this fashion, some additional anal ys is where field observations were reviewed in a quantitative fashion, refer to the scenario monogra

ph reviews (Crowley , 2015a and Crowley , 2015b). Data users are recommended to review the field observations to get a sense of the extent of activities within these exposure scenarios. **4.0 Protocol**  **Amendments and Deviations**  Amendments to and deviations fro m the study protocol are detailed below. For additional details, see the AHE400 study report on pages 11 - 14 as well as Appendix A on pages 504 - 538. The study amendments were reasonable accommodations to accomplish the research and deviations did not adversely impact the study

conduct or the exposure monitoring results.Page 20 of 22

Protocol Amendments:

 To increase likelihood of finding workers to monitor, additional employer sources were added: the same employer can be used in multiple monitoring areas; referrals f rom other employers; and, employers/companies the AHETF is aware of but not on the “ Employer Universe List” .  Because recruitment revealed that workers commonly wear chaps and leggings for physical protection, this was removed as an exclusion criterion.  Bec ause recruitment revealed that workers commonly wear (or are required by

their employers to wear) hard hats and boots that rise above mid - calf, those were removed as exclusion criteria.  Because recruitment specifically for electric and pipeline utility rights - of - way proved limiting, additional areas of similar brush/shrubs, foliage density /height, and terrain such as roadsides and wildlife refuges were added as possible sites.  Amended contact information for Principal Anal ytical Investigator and Analy tical Facility  Amended fosamine and imazapy r anal ytical methods sections to more accuratel y identify the methods following their complete development and validation.  Recruitment in the originally specified US states proved limiting, other states will be acceptab le.  Field fortification levels for dermal exposure monitoring methods were increased.  Recruitment proved difficult, so the “same employer” restriction was relaxed

– but with additional restrictions that if they had the same employer monitoring must occur in a separate year, a different job site, and a different application crew.  Changed gl yphosate analytical methods following addition of a derivatization step and added additional text specifying how this revised method was validated. Protocol Deviations

 F ield samples for MUs A8 and A9 as well as associated field fortification levels were anal yz ed for fosamine using analy tical methods not fully

identified in the protocol or by a protocol amendment. Though not identified in the protocol or amendment, at the time of anal ys is the method had been validated and finalized.  Unavailability

of test substances for purity anal ys is. Amount of active ingredient handled determined from product label and dilution rates.  Instances of less than 4 hours of monitoring time. Other application characteristics (tank loads, gallons sprayed, etc.) were still adequate and representative of typical workdays.  Lack of hand wash collection preceding a cigarette break.  Use of applicator’s own chemical - resistant gloves rather than AHETF - supplied chemical resistant gloves.  Failure to inform application company representative that they

would receive an AHETF introductory

letter.  Inhalation exposure pump off for extended periods of (non - exposure) time such as lunch breaks or rain events.  La ck of documentation of changes to anal ytical laboratory facilities.Page 21 of 22

**5.0 Conclusion**  As the studies followed their corresponding protocols a s well as EPA guidelines for occupational pesticide exposure monitoring, the results are reliable for assessment of expo sure and risk for backpack and handgun applications in utility rights - of - ways and other areas where chemical control of similar undesirable vegetation is conducted. Since th ese exposure data w ere collected with the intention to populate a generic pesticide exposure database, reviewers are directed to the additional information and statistical analyses in the AHETF Handgun ROW Scenario Monograph (Bruce, et al, 2 01 4 a) and the AHETF Backpack ROW Scenario Monograph (Bruce, et al, 2014b) . Review of those mon ographs as well as re commendations for use of the data by EPA exposure assessors are in a separate review memorandum ( Crowley , 201 5a and 2015b ). **6.0 References**  AHETF , ( 2008 ) . Volume IV AHETF Revised Governing Document for a Multi - Year Pesticide Handler Worker Exposure Monitoring Program. Version Number: 1. April 7, 2008. Agricultural Handlers Exposure Task Force (AHETF). [MRID 47172401] AHETF, (20 10 a). Monitoring Unit Selection and Construction Plan for Scenario s : 1. BACKPACK APPLICATION OF LIQUID SPRAYS IN UTILIT IES RIGHTS - OF - WAY 2. HANDGUN APPLICATION OF LIQUID SPRAYS I N UTILITIES RIGHTS - OF - WAY. June 4, 2010. AHETF, (2010b). Governing Document for a Multi - Year Pesticide Handler Exposure Monitoring Program, Version 2, August 12, 2010. Bruce, E. (201 4 ). Determination of Dermal and Inhalation Exposure to Workers d uring Backpack and Handgun Application of Liquid Sprays in Utilities Rights - of - Way . Study

Number AHE 400 . Unpublished study sponsored by the Agricultural Handler Exposure Task Force. 1430 p. September 18, 2014 . EPA MRID 4 9472001 . Bruce, E. , Holden, L. , and Klonne, D. (2014 a). Agricultural Handler Exposure Scenario Monograph: Handgun Applicati o n of Liquid Sprays in Utilities Rights - of - Way . Report Number AHE1013. Unpublish ed study sponsored b y the Agricultural Handlers Exposure Task Force. 218 p. September 29, 2014. EPA MRID 49478602. Bruce, E., Holden, L., and Klonne, D. (2014b). Agricultural Handler Exposure Scenario Monograph: Backpack Application of Liquid Sprays in Utilities Rights - of - Way . Report Number AHE1012. Unpublished study sponsored by

the Agricultural Handlers Exposure Task Force. 224 p. September 29, 2014. EPA MRID 49478601.Page 22 of 22

Crowley , M . (2015a). Memorandum: Review of Agricultural Handler Exposure Task Force (AHETF) Monograph: “Backpack Application of Liquid Sprays in Utilities Rights - of - Way” (AHE1012) . D 424145 . March 24 , 201 5 . Crowley , M . (2015b). Review of Agricultural Handler Exposure Task Force (AHETF) Monograph: “Handgun Application of Liquid Sprays in Utilities Rights - of - Way” (AHE1013). D 424145 . March 24, 2015 . NAFTA - Dept. of Pesticide Regulation (DPR), California EPA, HSM - 98014, April 24, 1998 .