Document ID: EPA-HQ-OPP-2006-0857-0008
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2008-02-27T05:00Z

U. S.  ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C. 20460-0001

OFFICE OF 

PREVENTION, PESTICIDES,

AND TOXIC SUBSTANCES 

MEMORANDUM

Date:	September 28, 2007  

Subject:	Cyfluthrin and Beta-Cyfluthrin: Occupational Risk Assessment to
Support the Uses on Alfalfa and Grasses and the Use of Beta-Cyfluthrin
on Sugar Beet.  Petition Nos. 6E7058 (Grasses), 6F7160 (Sugar Beet), and
7F7226 (Alfalfa).	 

Active Ingredients & (PC Codes):

Cyfluthrin (128831)

beta-Cyfluthrin (118831)	DP No:  D339445

Other DP Nos: D339415, D340710, D340711, D340712, and D340713

EPA. Reg. Nos: 264-745, 264-784,  and 264-840 Crops: Alfalfa and Grasses
Reg. No. 264-RNLA                           Crop: Sugar beet

Class: Insecticides	MRID:  47007811

From:	S. Oonnithan, Biologist

Registration Action Branch 2

Health Effects Division (7509 P)

Through:	Richard Loranger, Senior Scientist  

Registration Action Branch 2

Health Effects Division (7509 P)

To:	Dan Rosenblatt, Branch Chief, IMRUB Branch

George LaRocca, RM 13, Insecticide Branch 

Registration Division (7505 P)

This occupational risk assessment includes Petition Nos. 7F7226 and
6E7058 submitted by Bayer CropScience and Interregional Research Project
No. 4 (IR-4), respectively, to increase the seasonal application rates
of cyfluthrin and beta-cyfluthrin on alfalfa and grasses, respectively
and Petition No. 6F7160 submitted by Bayer CropScience to register a new
use, sugar beet as a seed treatment, to the registered uses of
beta-cyfluthrin.  Bayer CropScience has also applied to register a new
product formulation, Poncho Beta (EPA File Symbol: 264-RNLA) containing
beta-cyfluthrin and clothianidin as active ingredients (AIs/ais), for
the treatment of sugar beet seeds.  While this document contains the
occupational exposures and risk of beta-cyfluthrin in Poncho Beta, a
separate document (S. Oonnithan, D340131, 9/28/2007) addresses the
exposures and risks to clothianidin, the second AI present in the Poncho
Beta formulation.

TABLE OF CONTENTS

  TOC \o "1-2" \h \z \u    HYPERLINK \l "_Toc179184231"  1.0.  EXECUTIVE
SUMMARY	  PAGEREF _Toc179184231 \h  3  

  HYPERLINK \l "_Toc179184232"  2.0.  BACKGROUND	  PAGEREF _Toc179184232
\h  5  

  HYPERLINK \l "_Toc179184233"  3.0.  USE PATTERN	  PAGEREF
_Toc179184233 \h  5  

  HYPERLINK \l "_Toc179184234"  4.0.  HAZARD CHARACTERIZATION	  PAGEREF
_Toc179184234 \h  6  

  HYPERLINK \l "_Toc179184235"  5.0.  NON-OCCUPATIONAL AND RESIDENTIAL
EXPOSURES	  PAGEREF _Toc179184235 \h  7  

  HYPERLINK \l "_Toc179184236"  6.0.  OCCUPATIONAL EXPOSURES	  PAGEREF
_Toc179184236 \h  7  

  HYPERLINK \l "_Toc179184237"  6.1.  Use of Cyfluthrin and
beta-Cyfluthrin on Alfalfa and Grasses	  PAGEREF _Toc179184237 \h  7  

  HYPERLINK \l "_Toc179184238"  6.2.  Use of beta-Cyfluthrin on Sugar
Beet	  PAGEREF _Toc179184238 \h  12  

  HYPERLINK \l "_Toc179184239"  7.0.  POSTAPPLICATION EXPOSURES	 
PAGEREF _Toc179184239 \h  15  

  HYPERLINK \l "_Toc179184240"  7.1.  Use of Cyfluthrin and
beta-Cyfluthrin on Alfalfa and Grasses	  PAGEREF _Toc179184240 \h  15  

  HYPERLINK \l "_Toc179184241"  7.2. Use of beta-Cyfluthrin on Sugar
Beet	  PAGEREF _Toc179184241 \h  16  

  HYPERLINK \l "_Toc179184242"  8.0.  CONCLUSIONS AND RECOMMENDATIONS	 
PAGEREF _Toc179184242 \h  17  

  HYPERLINK \l "_Toc179184243"  9.0.  REFERENCES	  PAGEREF _Toc179184243
\h  17  

 

1.0.  EXECUTIVE SUMMARY

Use Patterns:  The petitioners are proposing to amend the labels of
cyfluthrin and beta-cyfluthrin to increase the maximum seasonal
application rates on alfalfa and grasses, without changing the maximum
single application rates.  The alfalfa crop may be grown for hay or
seeds and the grasses may be grown for pasture, rangeland, and/or hay
and seed, and in mixed-stands with alfalfa.  The submitted product
formulations include two emulsifiable concentrates (ECs) and a wettable
powder packed as water-soluble bags (WP/WSB).  Foliar applications are
made using aerial, ground boom, or chemigation equipment with a maximum
8 applications per season on alfalfa and 4 applications on grasses, all
at 5 day intervals.  On alfalfa and grasses, the maximum single
application rates are 0.044 and 0.022 lb ai/A for cyfluthrin and
beta-cyfluthrin, respectively.  The maximum seasonal rates for
cyfluthrin and beta-cyfluthrin on alfalfa are 0.35 and 0.176 lb ai/A
respectively, and that for grasses are 0.176 and 0.089 lb ai/A,
respectively 

In another submission, the petitioner is proposing to add sugar beet to
the uses of beta-cyfluthrin as a seed treatment.  For this purpose, a
new seed treatment liquid formulation, Poncho Beta is being registered. 
The sugar beet seeds may be treated with Poncho Beta (a ready-to-use
liquid concentrate) at a maximum rate of 0.0043 lb ai/ lb of seed, in a
commercial facility using liquid or slurry coating equipment.  The
treated seeds are stored until planted.

Hazard Characterization: Cyfluthrin and beta-cyfluthrin (an enriched
isomer of cyfluthrin) have been found to have similar toxicological
effects in animals and have neurotoxic type of mode of action.  They
have high to medium acute oral and inhalation toxicities, respectively,
and low dermal and eye irritation effects.  There is no potential for
increased susceptibility of infants and children to cyfluthrin and
therefore, Health Effects Division (HED) has concluded that no special
Food Quality Protection Act (FQPA) safety factor is necessary.  The
toxicology database is complete, so, the uncertainty factor (UF) remains
100, which also is HED's level of concern (LOC) for the margin of
exposure (MOE).  For assessing the occupational risks, HED has selected
the following doses for cyfluthrin and beta-cyfluthrin:  (i) short-and
intermediate-term dermal No Observed Adverse Effect Levels (NOAELs) of
2.36 mg/kg/day from a 90-day feeding study in dogs, (ii) a short-term
inhalation NOAEL of 0.07 mg/kg/day from a 28-day inhalation study in
rats, and (iii) an intermediate-term inhalation NOAEL of 0.02 mg/kg/day
from a 13-week inhalation study in rats. A dermal absorption factor of
5% was picked to estimate the dermal exposure since the dermal end point
was based on an oral study.  HED has determined that the dermal and
inhalation exposures can be combined to estimate the occupational risks
due to the same toxicity endpoints (clinical signs of neurotoxicity
and/or body weight effects).  Cyfluthrin was classified as “not likely
to be carcinogenic to humans.”

Non-Occupational and Residential Exposures:  There are several
cyfluthrin containing end-use products registered for use by home owners
and professional applicators for insect control in residential areas
including lawns.  An evaluation of such exposures has been done
recently, where the risks to home owners and children were found to be
below HED's LOC.  With this submission, the petitioners have not
proposed any new residential and/or non-occupational uses for cyfluthrin
and/or beta-cyfluthrin.

Occupational Exposures:  The proposed uses of cyfluthrin and
beta-cyfluthrin on alfalfa and grasses are expected to result in both
short- and intermediate-term exposures to mixers/loaders, applicators,
and flaggers.  Lacking product specific exposure data, the exposures
were estimated using surrogate values from the Pesticide Handler
Exposure Database (PHED) and Scientific Advisory Committee on Exposure
(ExpoSAC) Policy # 9.  Using the estimated exposure values and the
selected toxicity doses for each exposure route and duration, MOEs were
calculated for all applicable exposure scenarios of cyfluthrin and
beta-cyfluthrin. Then the dermal and inhalation MOEs were combined to
arrive at a total MOE for each duration, because the NOAELs were based
on the same toxicity endpoints.

The resulting total short-term risks to mixers and loaders are of
concern when they handle cyfluthrin and beta-cyfluthrin EC formulations
for aerial applications and cyfluthrin EC formulation for chemigation,
if they wear only label specified PPE.  The total intermediate-term 
risks also are of concern while handling cyfluthrin EC for ground boom
and beta-cyfluthrin EC for chemigation applications.  These higher risks
could be mitigated by adding a dust-mist respirator to the label
specified PPE.  For applicators and flaggers, both the total short- and
intermediate-term risks are not of concern if they wear label specified
PPE when applying formulations of cyfluthrin and beta-cyfluthrin using
aerial and/or ground equipment.

The total short- and intermediate-term risks to workers who treat sugar
beet seeds with Poncho Beta formulation, while wearing the label
specified PPEs are not of concern.  However, the total risks are of
concern for both exposure durations if one worker (worker type =
Multiple) handles all seed treatment steps like loading, treating,
bagging, and sewing, alone on a daily basis. In actual practice, such a
scenario is unlikely, due to the fact that one man operation will slow
down the process considerably making it uneconomical for a commercial
seed treatment facility.

Postapplication Exposures:  The risks to workers who enter cyfluthrin
and beta-cyfluthrin 

treated alfalfa and grass fields to do postapplication activities are
not of concern when assessed 

for short- and intermediate-term durations. Also, the total risks to
workers who plant the Poncho Beta treated sugar beet seeds are not of
concern when assessed for short- and intermediate-term durations.

2.0.  BACKGROUND

Cyfluthrin and beta-cyfluthrin (an enriched isomer of cyfluthrin) are
non-systemic synthetic pyrethroid insecticides registered for the
control of agricultural, household, lawn and garden and stored product
pests.  They are formulated into emulsifiable concentrates (ECs),
aerosols, foggers, granules, ultra-low-volume sprays and wettable
powders.  

3.0.  USE PATTERN

Alfalfa and Grasses:  The label amendments for increasing the seasonal
application rates of cyfluthrin and beta-cyfluthrin on alfalfa and
grasses involved the following three products:  Baythroid® 2
Emulsifiable Pyrethroid Insecticide (EPA Reg. Nos. 264-745, AI =
cyfluthrin), Renounce®  20WP Insecticide (EPA Reg. No. 264-784, AI =
cyfluthrin), and Baythroid® XL (EPA Reg. Nos. 264-840, AI =
beta-cyfluthrin).  The Baythroid® 2 Emulsifiable Pyrethroid Insecticide
and Baythroid®  XL are EC formulations and Renounce®  20WP Insecticide
is a wettable powder packaged as water-soluble bags (WSB).  The alfalfa
crop may be grown for seed as well as cutting.  The pre-gazing interval
(PGI) and preharvest interval (PHI) are 7 days for both cyfluthrin and
beta-cyfluthrin.  The grasses crop includes pasture, rangeland, grasses
grown for hay and seed, and in mixed-stands with alfalfa.  The PGI is 0
day for pasture, rangeland, and 7 days for seed crop and mixed-stands
with alfalfa.  The PHI is 0 day for grass hay.  Applications may be made
using aerial, ground boom, or chemigation (sprinkler) equipment.  ULV
applications by air may also be made using 1 quart/A of vegetable oil as
a carrier.  The proposed label amendments on alfalfa and grasses are to
increase the maximum seasonal application rates for cyfluthrin and
beta-cyfluthrin while maintaining the same maximum rates per application
(Table 1).

Table 1. Current and Proposed Application Rates for Cyfluthrin and
beta-Cyfluthrin on Alfalfa and Grasses 1.

Active Ingredients                  and Formulations	Alfalfa            
                                  Maximum Appl. Rates (lb ai/A)	Grasses 
                                             Maximum Appl. Rates (lb
ai/A)

	Current 2	Proposed	Current 2	Proposed

Cyfluthrin, Baythroid® 2 Emulsifiable Pyreth. Insecticide              
                     EPA Reg. No. 264-745 	single = 0.044

# appls = ~ 5

seasonal = 0.2	single = 0.044

# appls = 8 

seasonal = 0.35	single = 0.044

# appls = 3

seasonal = 0.131	single = 0.044         # appls = 4

seasonal = 0.176

Cyfluthrin, Renounce®  20WP Insecticide,                     EPA Reg.
No. 264-784 	single = 0.044

# appls = ~ 5

seasonal = 0.2	single = 0.044

# appls = 8 

seasonal = 0.35	not on label 3	single = 0.044                           
       # appls = 4

seasonal = 0.176

Beta-cyfluthrin,                 Baythroid®  XL,                    
EPA Reg. No. 264-840                                             	single
= 0.022

# appls = 4

seasonal = 0.088	single = 0.022

# appls = 8

seasonal = 0.176	single = 0.022

# appls = 3

seasonal = 0.066	single = 0.022               # appls = 4

seasonal = 0.089

1. Petition No. 7F7226 on alfalfa was submitted by Bayer CropScience and
Petition No. 6E7058 on grasses was submitted by IR-4.

2. From the current labels: Reg. Nos and (approved dates) Reg. 240-745
and Reg. No. 264-784 (04/11/2007) and Reg. No. 264-840 (01/16/2007). 

3.  Grasses are being added as a new site  

Sugar Beet: Bayer CropScience has submitted an application for
registering a new formulation, Poncho Beta (EPA File Symbol: 264-RNLA)
for the seed treatment of sugar beet.  It contains clothianidin and
beta-cyfluthrin at 34.3% (3.33 lb ai/gal) and 4.6%, (0.44 lb ai/gal),
respectively.  It is a liquid formulation used without dilution.  The
sugar beet seeds are to be treated in a commercial facility using liquid
or slurry coating equipment at the rate of 5.07 fl. oz of product per 1
unit seed (1 unit = 100,000 seeds).  At a seed weight of 4.085 lbs per 1
unit seeds, the maximum application rate amounts to 0.0043 lb
beta-cyfluthrin and 0.032 lb clothianidin per lb of seed.  [The
conversion factors used are: 1 unit sugar beet seeds contain 100,000
seeds (from label), 1.0 lb of sugar beet seed contains 24,480 seeds
(ExpoSAC Policy No. 15), and therefore, 1 unit seeds weigh 4.085 lbs]. 

4.0.  HAZARD CHARACTERIZATION

Cyfluthrin insecticide has a neurotoxic mode of action.  Its acute oral
toxicity is high; but, it has medium to low inhalation and dermal
toxicities.  The acute toxicity properties of cyfluthrin technical are
summarized in Table 2.

Table 2.  Acute Toxicity Profile of Cyfluthrin Technical.

G.L. No.	Study Type	Results	Toxicity Category

870.1100	Acute Oral Toxicity (Rats)	

LD50  (M) = 16.2 mg/kg 	I

870.1200	Acute Dermal Toxicity (Rabbits)	

LD50  (M&F) > 5000 mg/kg 

LD50  (M&F)> 5000 mg/kg	IV

870.1300	Acute Inhalation (Rats)	

LC50 (M) > 0.735 mg/L

LC50 (F)  =  0.468 mg/L	II

870.2400	Primary Eye Irritation (Rabbits)	

No corneal opacity; transient irritation for 3 days.	III

870.2500	Primary Dermal Irritation (Rabbits)	

Non-irritating 	IV

870.2600	Skin Sensitization 	

Not a sensitizer (Draize test)	N/A

Cyfluthrin and beta-cyfluthrin (an enriched isomer of cyfluthrin) have
been found to have similar toxicological effects; therefore HED has
combined the toxicology data bases to select the doses and endpoints
used in the risk assessment of both active ingredients.  The potential
for increased susceptibility of infants and children to cyfluthrin was
assessed and HED has concluded that no special FQPA safety factor is
necessary.  The toxicology database on cyfluthrin is essentially
complete, therefore, the UF remains 100, which also is the LOC for the
MOE.  HED has determined that the dermal and inhalation exposures can be
combined to estimate the occupational risks due to the same toxicity
endpoints (clinical signs of neurotoxicity and/or body weight effects). 
Cyfluthrin was classified as “not likely to be carcinogenic to
humans.”  The toxicological doses used for the short- and
intermediate-term risk assessment are summarized in Table 3.



Table 3.	 Toxicological Doses Selected for Occupational Risk Assessment
of Cyfluthrin and beta-Cyfluthrin.

Exposure Scenario	Doses 1	Study and Toxicological Effects

Dermal, Short-term        (1-30 days) and Intermediate-term   (1-6
months) 	NOAEL=2.36 mg/kg/day           DAF = 5 %                       
                                           MOE = 100 is LOC	90-Day
feeding study, dog  (beta-cyfluthrin)

LOAEL = 13.9/15.4 mg/kg/day for males/females, respectively, based on
decreased body weight gain, gait abnormalities, and increased incidence
of vomiting.

Inhalation              Short-term               (1-30 days) 	NOAEL=0.07
mg/kg/day        IAF= 100 %                           MOE = 100 is LOC
28-Day inhalation study, rat  (beta-cyfluthrin) 

LOAEL = 0.73 mg/kg/day based on decreases in body weight in both sexes
and decreased urinary pH in males.

Inhalation 

Intermediate-term  

(1-6 Months )	NOAEL= 0.02 mg/kg/day

IAF = 100 %  

MOE = 100 is LOC	13-Week inhalation study, rat (cyfluthrin)

LOAEL= 0.16 mg/kg/day based on decreases in body weight and body weight
gain in males and clinical signs in females

Cancer	Classified as "Not likely to be a carcinogen"

1. DAF = Dermal absorption factor, IAF = Inhalation absorption factor,
LOAEL = Lowest observed adverse effect  level, LOC = Level of concern,
MOE= Margin of exposure, NOAEL = No observed adverse effect level.

5.0.  NON-OCCUPATIONAL AND RESIDENTIAL EXPOSURES

There are several cyfluthrin containing end-use product formulations
registered for use by home owners and professional applicators for
controlling a variety of residential insect pests including lawns. 
These products are packaged or applied as aerosols-, crack and crevice
sprays, surface sprays and total release foggers.  Use of these products
results in residential and/or non-occupational exposures to cyfluthrin. 
An evaluation of such exposures has been done recently, where the risks
to home owners and children were found to be below HED's LOC (Wang,
D296251, 02/18/2005).  For this petition, the registrant has not
proposed any new residential and/or non-occupational uses; therefore, a
new residential/non-occupational exposure assessment was not performed
at this time for cyfluthrin and beta-cyfluthrin.

6.0.  OCCUPATIONAL EXPOSURES

6.1.  Use of Cyfluthrin and beta-Cyfluthrin on Alfalfa and Grasses

Exposure Characterization:  A previous assessment on cyfluthrin reviewed
the occupational risks from its use as an agricultural insecticide (S-C
Wang, D296251, 02/18/2005).  The proposed use pattern of cyfluthrin and
beta-cyfluthrin on alfalfa and grasses is expected to result in both a
short- (1-30 days) and an intermediate-term (1-6 months) exposure
because, on alfalfa, a maximum of 8 applications per season and on
grasses, a  maximum of 4 applications per season are applied, both at 5
day intervals.  The applicable exposure scenarios based on formulation
types, application methods, and worker types for the use of both
chemicals on alfalfa and grasses are summarized in Table 4.



Table 4. Short- and Intermediate-term Occupational Exposure Scenarios
Applicable for the Proposed 	Uses of Cyfluthrin and beta-Cyfluthrin on
Alfalfa and Grasses.

No.	Exposure Scenarios	Active Ingredient

--	Mixing/Loading:	Cyfluthrin

1	liquid, open mixing/loading for aerial, fixed wing and rotary
equipment	Cyfluthrin

2	liquid, open mixing/loading for ground boom equipment	Cyfluthrin

3	liquid, open mixing/loading for chemigation	Cyfluthrin

4	WP/WSB, open mixing/loading for aerial equipment 	Cyfluthrin

5	WP/WSB, open mixing/loading for ground boom equipment	Cyfluthrin

6	WP/WSB, open mixing/loading for chemigation	Cyfluthrin

7	liquid, open mixing/loading for aerial equipment	beta-Cyfluthrin

8	liquid, open mixing/loading for ground boom equipment	beta-Cyfluthrin

9	liquid, open mixing/loading for chemigation	beta-Cyfluthrin

--	Applying/Flagging:

	10	liquid and WP, applying by aerial fixed wing equipment, enclosed cab
	Cyfluthrin

11	liquid and WP, applying by aerial rotary equipment, enclosed cab 
Cyfluthrin

12	liquid and WP, applying by ground boom equipment, open cab	Cyfluthrin

13	liquid and WP, flagging, aerial applications	Cyfluthrin

14	liquid, applying by aerial fixed wing equipment, enclosed cab 
beta-Cyfluthrin

15	liquid, applying by aerial rotary equipment, enclosed cab 
beta-Cyfluthrin

16	liquid, applying by ground boom equipment, open cab	beta-Cyfluthrin

17	liquid, flagging, aerial application 	beta-Cyfluthrin 

The labels of cyfluthrin (Baythroid® 2 Emulsifiable Pyrethroid
Insecticide and Renounce®  20 WP Insecticide) and beta-cyfluthrin
(Baythroid®  XL) specify a basic PPE (long-sleeved shirt and long
pants, socks, and shoes) plus chemical resistant gloves, and protective
eye-wear (not on  EPA Reg. No. 264-784 label) for handlers with a
restricted entry interval of (REI) of 12-hours.  For this submission,
the petitioner has not submitted any product specific occupational
exposure data for estimating occupational exposures; therefore, the
surrogate values from PHED and ExpoSAC SOP # 9 were used to calculate
the exposures to the handlers.  The default values and other assumptions
and parameters used for this assessment are summarized in Table 5.

Table 5.	 Assumptions and Parameters Used for Assessing the Exposures
and Risk to Handlers From the Use 	 of Cyfluthrin and beta-Cyfluthrin on
Alfalfa and Grasses.

Details	Values

- maximum single appl. rate on alfalfa and grasses (from Table 1) 
cyfluthrin - 0.044 lb ai/A 

beta-cyfluthrin - 0.022 lb ai/A

- application equipment used 	aerial, ground boom, and chemigation

- area (Acres) treated/day                       (ExpoSAC Policy SOP #
9) 	aerial - 1200  		ground boom - 200

chemigation - 350 	flaggers - 350 

- work duration/day	8 hrs

- types of exposures assessed 	short- (1-30 days/year) and intermediate
term 

- body weight of workers 	70 lb 

- unit exposures	from PHED

The following equations were used to estimate the non-cancer short- and
intermediate-term exposures and risks to handlers when cyfluthrin and
beta-cyfluthrin formulations are applied on alfalfa and grasses.  

Equation No. 1.  DD =  [AR * AT * DUE * DAF * CF2] / BW

Equation No. 2.  ID =  [AR * AT * IUE * CF1 * IAF * CF2] / BW

Equation No. 3. DMOE = DNOAEL/ DD

Equation No. 4. IMOE = INOAEL/ ID

Equation No. 5. Total MOE = 1/[(1/DMOE) + (1/IMOE)] for short-term or
intermediate-term 	           	   exposure durations

Where, 

AR		=  maximum single application rate 

AT		=  area treated/day (acres)

BW		=  body weight of workers 

	CF1		=  conversion factor 0.001 for µg/lb ai to mg/lb ai

CF2		=  conversion factor 0.01 for %

DAF		=  dermal absorption factor (%) 

DUE		=  dermal unit exposure (mg/lb ai)

DD		=  dermal dose for ai handled (mg/kg/day)

IAF		=  inhalation absorption factor  (%)

ID		=  inhalation dose for the ai handled (mg/kg/day)

IUE		=  inhalation unit exposure (µg/lb ai)

	DMOE		=  dermal MOE (short- or intermediate-term)

IMOE		=  inhalation MOE  (short- or intermediate-term)

DNOAEL	=  dermal NOAEL (short- or intermediate-term)

INOAEL	=  inhalation NOAEL  (short- or intermediate-term) 



Table 6.  Short- and Intermediate-term Occupational Risks to
Mixers/Loaders From the Use of Cyfluthrin and beta-Cyfluthrin on Alfalfa
and Grasses 1

Chemical	Mixing/Loading Exposure                                
Scenario  #	

PPE 2	Dermal Unit Exposure         (mg/lb ai)	Inhalation Unit Exposure  
(µg/lb ai)	Dermal Dose                     (mg/kg/day) 3	Inhal. Dose  
(mg/kg/day) 4 	Total        Short-term          MOE 5	Total     
Interm.- term           MOE 5

Cyfluthrin	1. Liquid, Open, Aerial	BL	2.9	1.2	0.109371	0.000905	17	11

"         "	1a.    "	 "	BL+G+R	0.023	0.24*	0.000867	0.000181	340	110

"         "	2. Liquid, Open,        Ground boom 	BL	2.9	1.2	0.018229
0.000151	100	66

"         "	2a.    "	 "	BL+G+R	2.9	0.24*	0.018229	0.000030	120	110

"         "	3. Liquid, Open, Chemigation	BL	2.9	1.2	0.031900	0.000264	58
37

"         "	3a.    "	 "	BL+G+R	0.023	0.24*	0.000253	0.000053	1,200	360

"         "	4. WP/WSB, Open, Aerial 	BL	0.021	0.24	0.000792	0.000181	340
110

"         "	5. WP/WSB, Open,   Ground boom	BL	0.021	0.24	0.000132
0.000030	2,100	640

"         "	6. WP/WSB, Open, Chemigation 	BL	0.021	0.24	0.000231
0.000053	1,200	370

Beta-cyfluthrin	7. Liquid, Open, Aerial	BL	2.9	1.2	0.054686	0.000453	34
22

"         "	7a.    "	 "	BL+G+R	0.023	0.24*	0.000434	0.000091	680	210

"         "	8. Liquid, Open,           Ground  boom 	BL	2.9	1.2	0.009114
0.000075	200	130

"         "	9. Liquid, Open, Chemigation	BL	2.9	1.2	0.015950	0.000132
120	75

"         "	9a.    "	 "	BL+G+R	2.9	0.24*	0.015950	0.000026	140	120

1.  Exposure scenarios, values, and assumptions are from Tables 1, 3, 4,
and 5.

2.  BL = baseline PPE (long-sleeve shirt, long pants, shoes with socks,
and no respirator), G = Gloves, R = dust-mist respirator.

3.  Dermal dose/day =  Equation No. 1.

4.  Inhalation dose/day = Equation No. 2

5.  Total Short-term or Total Intermediate-term MOE (Equation No. 5) 

*.  Applied an 80% reduction factor to the inhalation unit exposures for
the use of dust/mist respirator as a mitigation measure. Ref: Exposure
mitigating Table (PHED).  



Table 7.  Short- and Intermediate-term Occupational Risks to Applicators
From the Use of Cyfluthrin and beta-Cyfluthrin on Alfalfa and Grasses  1

Chemical	Mixing/Loading Exposure                                
Scenario  #	

PPE 2	Dermal  Unit Exposure (mg/lb ai)	Inhalation Unit Exp.  (µg/lb ai)
Dermal Dose                     (mg/kg/day) 3	Inhal. Dose   (mg/kg/day)
4 	Total        Short-term          MOE 5	Total      Interm.- term      
    MOE 5

Cyfluthrin	10. Liquid & WP, Aerial, Fixed wing, Enclosed cab	BL	0.005
0.068	0.000189	0.000051	1,200	380

"         "	11. Liquid & WP, Aerial, Rotary, Enclosed cab	BL	0.0019
0.0018	0.000072	0.0000014	20,000	10,000

"         "	12. Liquid & WP, Gr. boom,  Open cab	BL	0.014	0.74	0.000088
0.000093	730	210

"         "	13. Liquid & WP, Aerial, Flagger	BL	0.011	0.35	0.000121
0.000077	870	260

Beta-cyfluthrin	14. Liquid & WP, Aerial, Fixed Wing, Enclosed cab	BL
0.005	0.068	0.000094	0.000026	2,500	760

"         "	15. Liquid & WP, Aerial, Rotary, Enclosed cab	BL	0.0019
0.0018	0.000036	0.000001	40,000	20,000

"         "	16. Liquid & WP, Gr. boom,  Open cab	BL	0.014	0.74	0.000044
0.000047	1,500	430

"         "	17. Liquid & WP, Aerial, Flagger	BL	0.011	0.35	0.000061
0.000039	1,700	510

1.  Exposure scenarios, values, and assumptions are from Tables 1, 3, 4,
and 5.

2.  BL = baseline PPE, G = Gloves, R = dust/mist respirator; baseline
PPE consists of long-sleeve shirt, long pants, shoes with socks and no
respirator. 

3.  Dermal dose/day =  Equation No. 1.

4.  Inhalation dose/day = Equation No. 2

5.  Total Short-term or Total Intermediate-term MOE (Equation No. 5) 

Table 6 summarizes the total (dermal and inhalation) short- and
intermediate-term non-cancer risks to mixers and loaders from exposures
to cyfluthrin and beta-cyfluthrin when liquid and WP/WSB formulations
are handled for aerial and ground applications on alfalfa and grasses. 
Using the dermal dose/day and the short- or intermediate- term dermal
NOAEL (same in this case), the dermal MOEs were calculated for each
exposure duration.  Similarly inhalation MOEs were calculated using the
inhalation dose/day and the short- or intermediate- term inhalation
NOAELs.  Then the dermal and inhalation MOEs for each exposure duration
were combined to arrive at total MOEs for the short- and
intermediate-term durations and for each of the exposure scenarios.  For
cyfluthrin, HED's LOC is 100; thus, a calculated MOE of  <100 is of
concern requiring mitigation/protection measures.

The short-term combined risk for mixers/loaders wearing only baseline
PPE indicates that handling the liquid formulations (ECs) of cyfluthrin
and beta-cyfluthrin for aerial applications resulted in risk of concern
which is a reflection of the higher quantity of AIs handled/day
(scenarios 1 and 7, Table 6).  Handling the EC formulation of cyfluthrin
for chemigation also resulted in MOE of 58 (LOC = 100).  Further
analysis of the individual short-term dermal and short-term inhalation
MOEs (not shown here) indicated that the higher risk was from the
inhalation route.  Therefore, use of a dust-mist respirator was added to
the baseline PPE plus gloves which provided adequate protection to the
mixers and loaders (scenarios 1a, 3a, and 7a) from higher exposures. 
When the intermediate-term combined risks to mixers/loaders were
considered, handling the EC formulation for ground boom (cyfluthrin,
scenario 2) and that for chemigation (beta-cyfluthrin, scenario 9)
applications were of concern.  Here also, the inhalation exposures were
found to be the contributing factor and use of a dust-mist respirator
mitigated the risks.  Handling the WP/WSB formulation of cyfluthrin for
aerial and ground applications was not of concern for both exposure
durations (scenarios 4, 5, and 6).

Table 7 summarizes the short-term combined and intermediate-term
combined risks to applicators and flaggers from cyfluthrin (EC and
WP/WSB formulations) and beta-cyfluthrin (EC) when applied using aerial
and ground equipment.  The results indicate that the baseline PPEs are
adequate (MOEs > 260, LOC = 100) to protect the applicators flaggers
when these formulations are applied on alfalfa and grasses.

The PPEs specified on the labels of all the three formulations (baseline
PPE plus rubber resistant gloves) are adequate for some of the proposed
mixing/loading scenarios and for applicators and flaggers.  But, some
other mixing/loading scenarios require in addition to the label
specified PPE, use of a dust-mist respirator for adequate protection of
handlers when higher quantity of AIs are handled/day, such as ECs for
aerial applications.

6.2.  Use of beta-Cyfluthrin on Sugar Beet

Exposure Characterization:  The petitioner has submitted an occupational
risk assessment summary (MRID 47007811) with this application.  But, it
was not reviewed because it did not contain any original occupational
exposure data. 

The proposed use pattern for sugar beet indicates, that during the seed
treatment season, the workers may be treating several batches of seeds
per day for several weeks resulting in short- (1-30 days) and
intermediate-term (1-6 months) exposures to the workers.  The Poncho
Beta is a ready-to-use (RTU) formulation, therefore, no mixing with a
diluent is required prior to pouring it in the seed treatment equipment.
 The likely occupational exposure scenarios for the sugar beet seed
treatment are the following:

•	loader/applicator who transfers the formulation and treats the seeds

•	bagger of treated seeds

•	sewer of bags after filling with the treated seeds

•	workers doing multiple activities (in a small seed treatment setup,
all the operations may be performed by the same worker).

Table 8.	 Application Rates and Other Parameters Used for Estimating
Worker Exposures to  	beta-Cyfluthrin. 

Details	Values

AIs in Poncho Beta formulation			beta-Cyfluthrin and Clothianidin

Conc. of beta-Cyfluthrin in Poncho Beta		0.44 lb ai/gal (per label)

Proposed appl. rate of Poncho Beta			5.07 fl. oz./1 Unit seed (per
label)

1 Unit seed 					100,000 sugar beet seeds (per label)

Conc. of beta-Cyfluthrin in 5.07 fl. oz		0.0174 lb ai [(0.44/128)*5.07]
/1 Unit seed

No. of sugar beet seeds per lb  	24,480 1 

Weight of 1 Unit sugar beet seeds	4.085 lbs (100,000)/24,480)

Proposed seed treatment method  	commercial 

Conc. of AI / lb of seed 	0.0043 lb ai (0.0174/4.085)

Treating and Planting	--

Quantity of seeds treated per day	52,000 1  (ranges13,200 to 105,600)
lbs

Area planted	80 A/day 1

Quantity of seed planted	640 lbs/day 1

Average work day 	8 hrs

Expected frequency of exposures 	short-term (1-30 days) and intermediate
term             (1-6 months)/year

Body weight of workers 	70 lb  

Unit exposures 	from ExpoSAC Policy # 14 2

1. ExpoSAC Policy No. 15, dated March 4, 2004.  

2. ExpoSAC Policy No. 14, dated May 1, 2003.  

Lacking  product specific exposure data for estimating the occupational
exposures to the workers, surrogate exposure values from HED's Standard
Operating Procedures (SOPs) No. 14 and No. 15 were used and these are
presented in Table 8.  The formulas used to estimate the non-cancer
short- and intermediate-term exposures and risks to the workers are the
same that used for estimating the exposures to handlers of cyfluthrin
and beta-cyfluthrin formulations for use on alfalfa and grasses (Section
6.1), except for the area treated per day was substituted with quantity
of seeds (lbs) treated or planted per day.

The Poncho Beta label specifies the following PPEs: (i) loaders/treaters
must wear long sleeved shirt and long pants, shoes with socks, chemical
resistant gloves, and dust/mist respirator and   (ii) baggers and sewers
must wear long sleeved shirt and long pants, shoes with socks, and
dust/mist respirator.  



Table 9.  Short- and Intermediate-Term Risks to Seed Treatment Workers
and Planters From the Use of beta-Cyfluthrin Containing Poncho Beta on
Sugar 	  Beet. 1

Exposure

Scenarios	Worker   

Type	

PPE 2	Qty Treated / Planted/day      (lbs)	Unit Exp. Dermal/day

(mg/lb ai)	Unit Exp. Inhal./day

(µg/lb ai)	Dermal 

Dose/day

(mg/kg) 3 	Inhalation

Dose/day 

(mg/kg) 4	Total        Short-term          MOE 5	Total      Interm.-
term           MOE 5

Loading/Treating	L/T	S, G	52,000	0.023	0.34	0.00365	0.00108	59	18

Loading/Treating	L/T	S, G, R	52,000	0.023	0.068 *	0.00365	0.00022	220	81

Bagging, treated seed	Bagger	S	52,000	0.0091	0.16	0.00144	0.00051	130	38

Bagging, treated seed	Bagger	S, R	52,000	0.0091	0.032 *	0.00144	0.00010
490	180

Sewing, bagged seed	Sewer	S	52,000	0.0062	0.23	0.00098	0.00073	92	27

Sewing, bagged seed	Sewer	S, R	52,000	0.0062	0.046 *	0.00098	0.00015	400
130

Doing multiple jobs	Multiple	S, G	52,000	0.0420	1.6	0.00666	0.00508	13	4

Doing multiple jobs	Multiple	S, G, R	52,000	0.0420	0.32 *	0.00666
0.00102	58	19

Handling/ Planting 6 	Farmer, Postappl.	S, #	640	0.25	3.4	0.00049
0.00013	470	150

1.  Parameters and assumptions are from Tables 3 and 8.

2.  S = Single layer (long sleeve shirt and long pants) and no gloves, G
= chemical resistant gloves, R = dust/mist respirator  

3.  Dermal dose =  Equation No. 1.

4.  Inhalation dose = Equation No. 2

5.  Total Short-term or Total Intermediate-term MOE (Equation No. 5) 

6.  Postapplication exposure.

* Applied an 80% reduction factor to the inhalation unit exposure for
the use of dust/mist respirator, which is a PPE requirement on the label
for all seed treatment workers. Ref: Exposure Mitigating Table (PHED).

#.  For handlers/planters, label specifies gloves for loading only.

Table 9 summarizes the total (dermal and inhalation) short-term or
intermediate-term non-cancer risks to workers who do the sugar beet seed
treatment in a commercial facility with Poncho Beta containing
beta-cyfluthrin.  The estimated total short-term MOEs indicate that all
workers, except the worker who does multiple steps of seed treatment are
adequately protected, provided they all wear label specified PPE
[baseline + gloves (except baggers and sewers) + dust-mist respirator]. 
Similarly, the total intermediate-term MOEs indicate that the worker who
load/treat the sugar beet seeds are exposed to a higher risk (MOE = 81,
LOC = 100) than baggers and sewers if they wear baseline PPE plus
dust-mist respirator.  For the worker who does multiple jobs, even with
the use of a dust-mist respirator, the total short- and total
intermediate-term risks are of concern (MOEs of 4 and 19, respectively).
 In actual practice, such a scenario is unlikely, due to the fact that
one man operation will slow down the process considerably making it
uneconomical for a commercial seed treatment facility.

7.0.  POSTAPPLICATION EXPOSURES

7.1.  Use of Cyfluthrin and beta-Cyfluthrin on Alfalfa and Grasses

Exposure Characterization:  Postapplication dermal exposure to
cyfluthrin and beta-cyfluthrin is likely when workers enter the treated
fields under alfalfa and grasses to do irrigation, scouting, harvesting,
etc.  No inhalation exposure is expected during such post-treatment farm
activities.   Most of these postapplication operations are performed
using mechanical equipment, thus reducing the worker exposure, but
scouting of alfalfa and grasses grown for seeds is expected to result in
result in measurable exposures.

The postapplication worker exposures were estimated using surrogate
dermal transfer coefficient (TC) values from the ExpoSAC Policy No. 3.1
database.  For the alfalfa crop, the highest TC was for scouting as
compared with other activities.  For the grass crop, lacking the crop
specific TC values, representative values from a surrogate crop, alfalfa
were used. 

  The equations and inputs used for calculating the postapplication
exposures are the following:

Equation No. 1: DFR	=  AR * F * (1-D)t * CF1 * CF2

	Equation No. 2: DD =  (DFR * CF3 * TC *  DA *  ET) /  BW

	Equation No. 3: MOE	=  NOAEL / DD  

where:

AR		=  application rate for the crop  (max. lb ai/A/Application)

BW		=  body weight (70 kg)

	CF1		=  4.54 E+8 conversion factor for µg/lb AI

	CF2		=  2.47E-8 conversion factor for Acre/cm2

CF3		=  10E-3 conversion factor for mg/µg AI

(1-D)t 		=  fraction of residue that dissipates daily (default 10%)

DA		=  dermal absorption factor (%/100)

DDt		=   dermal dose (mg/kg/day) on day 't'

DFRt		=  dislodgeable foliar residue on day 't' (µg/cm2)

ET		=  exposure time (8 hours)

F		=  fraction of AI retained on foliage (default 20%)

NOAEL	=  from Table 3

t	=   number of days after application; (default 0 day, after the REI). 

	TC		=  transfer coefficient 

Table 10 summarizes the short- and intermediate-term dermal exposures
and risks to workers who may enter cyfluthrin and beta-cyfluthrin
treated fields of alfalfa and grasses.  The short- and intermediate-term
MOEs are the same for cyfluthrin because of the same toxicity endpoint
for both exposure durations.  The results indicate that the MOEs are of
no concern (MOE = 2,800, LOC = 100) to the postapplication workers.

Table 10. Short-and Intermediate-Term Postapplication Risks to Workers
Who Enter Alfalfa and Grass 	   Fields Treated with Cyfluthrin and
beta-Cyfluthrin.  

Crops 1	Chemical	Max. Single Appl. Rate (lb ai/A)	DFR        µg/cm2
Transfer Coefficient 3	Dermal Dose  (mg/kg/day) 4	Sh. & Inter.-term MOE
5

Alfalfa and Grass grown for seed 	cyfluthrin	0.044	0.099	1500 scouting 
0.00085	2,800

	beta-cyfluthrin	0.022	0.049	1500 scouting 	0.00042	5,600

1.  Among the grass crop sites (pasture, rangeland, grasses grown for
hay and seed, grass mixed-stands with alfalfa), grass grown for seed is
expected to have the maximum postapplication activities.

2.  DFR is calculated using Equation No. 1 above.

3. Transfer coefficient (TC) is for alfalfa (surrogate crop) with medium
exposure potential.

4. Dermal Dose (DD) is calculated using Equation No. 2 above.

5. Dermal MOE is calculated using Equation No. 3 above.  Short- and
Intermediate-term MOEs are the same because of the same NOAELs for these
durations.

7.2. Use of beta-Cyfluthrin on Sugar Beet

Exposure Characterization:  The postapplication exposure to
beta-cyfluthrin is likely when planters transfer the treated seeds from
bags to planter-hopper and/or while planting/drilling the seeds.  HED
has determined that the handling and planting of treated sugar beet
seeds involve both dermal and inhalation exposures even if the treated
seeds are not contacted directly.  It is assumed that the sugar beet
planting season may last for >30 days/season resulting in short- and
intermediate-term exposures to planters.

The postapplication exposure to planters was estimated using surrogate
values from HED's SOPs No. 14 and No. 15 and the results are presented
in Table 9.  The estimated total short- and intermediate-term risks are
not of concern (MOEs 470 and 150 respectively) to planters of Poncho
Beta treated sugar beet seeds.  While the planters are seeding/planting,
no direct contact with the treated seeds are expected, as the planting
machinery places/drills the seed and covers it with soil, doing both
steps in one operation.  The treated seeds once covered with soil are
protective of workers who may reenter the field soon after planting for
irrigation.  No other postapplication activity is performed in a freshly
seeded sugar beet field.  There is no restricted entry interval (REI)
for treating and planting of pre-treated seeds as REI is not applicable
for seed treatment operations.

8.0.  CONCLUSIONS AND RECOMMENDATIONS

1.	The total short-term risks to mixers/loaders are of concern when they
handle (i) cyfluthrin and beta-cyfluthrin EC formulations for aerial
applications and (ii) cyfluthrin EC formulation for chemigation, if they
wear only label specified PPE.  The total intermediate-term risks also
are of concern while handling cyfluthrin EC for ground boom and
beta-cyfluthrin EC for chemigation applications.  These higher risks
could be mitigated by adding a dust-mist respirator to the label
specified PPE.

2.	Both the total short- and intermediate-term risks are not of concern
for applicators and flaggers wearing label specified PPE when applying
formulations of cyfluthrin and beta-cyfluthrin on alfalfa and grasses
using aerial and/or ground equipment.

3. 	The total short- and intermediate-term risks to workers who treat
sugar beet seeds with Poncho Beta formulation, while wearing the label
specified PPEs are not of concern.  However, the total risks are of
concern for both exposure durations if one worker handles all seed
treatment steps like loading, treating, bagging, and sewing, alone on a
daily basis.

4.	The risks to workers who enter cyfluthrin and beta-cyfluthrin treated
alfalfa and grass fields to do postapplication activities are not of
concern when assessed for short- and intermediate-term durations.

5.	The total risks to workers who plant/drill the Poncho Beta treated
sugar beet seeds are not of concern when assessed for short- and
intermediate-term durations.

9.0.  REFERENCES

MRID 47007811,  Lunchick, C. Poncho Beta Sugar Beet Seed Treatment
Worker Risk Assessment, Bayer CropScience, Research Triangle Park, NC
27709, Nov. 28, 2006, 7 pp.

Oonnithan, S., D340131, 9/28/2007.  Clothianidin: Occupational Exposure
Assessment for the Use of Clothianidin as a Seed Treatment Formulation
for Sugar Beet Seeds.

Pesticide Handler Exposure Database (PHED) Surrogate Exposure Guide,
Version 1.1, August 1998. OPP, US EPA.

Science Advisory Council for Exposure Policy No. 3.1. Agriculture
Default Coefficients, August 7, 2000. OPP, US EPA.

Science Advisory Council for Exposure Policy No. 9.  Standard Values for
Daily Acres Treated in Agriculture, July 5, 2000. OPP, US EPA.

Science Advisory Council for Exposure Policy No. 14.  Standard Operating
Procedure (SOP) for Seed Treatment, May 1, 2003. OPP, US EPA. 

Science Advisory Council for Exposure Policy No. 15.  Standard Operating
Procedure (SOP):  Amount of Seed Treated and Planted per Day, March 2,
2004. OPP, US EPA.

Wang, S-C.; D296251, 02/18/2005. Occupational and Residential
Exposure/Risk Assessment for the New Uses of Cyfluthrin on Wheat, Leafy
Vegetables, Leafy Brassica Greens, Fruiting Vegetables, Cucurbit
Vegetables, Pome Fruits, Stone Fruits, Tree Nuts, Grapes, Peanuts,
Pea/Beans and Grasses.

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