# Registration Review

Ecological Risk Assessment and Effects

Determinations

Carbon, Carbon Dioxide, Sawdust, Sodium Nitrate, Potassium Nitrate and Sulfur Gas Cartridges

Environmental Fate and Effects Division Office of Pesticide Programs Washington, D.C. 20460

March 30, 2010

Primary Authors: ERB V Secondary Review: Valerie Woodard, Ph.D., Biologist Environmental Fate
and Effects Div. Edward Odenkirchen, Senior
Scientist José L. Meléndez, Chemist Mah T. Shamim, Ph.D., Chief

### Table of Contents

1 Executive Summary ...............................................................................................3

2. Problem Formulation ..........................................................................................13

2.1 Purpose ..........................................................................................................................14
2.2 Scope ..............................................................................................................................1 5
2.3 Previous Assessments ...................................................................................................16
2.4 Stressor Source and Distribution ...............................................................................17
2.5 Action Area ...................................................................................................................22
2.6 Ecosystems Potentially at Risk ...................................................................................23
2.7 Receptors ......................................................................................................................23
2.8 Assessment Endpoints and Measures of Ecological Effect ......................................23
2.9 Conceptual Model ........................................................................................................26
2.10 Analysis Plan ................................................................................................................29

3. Exposure Assessment ...........................................................................................30

3.1 Label Application Rates and Intervals ......................................................................30
3.2 Terrestrial Animal Exposure Assessment .................................................................30
3.3 Terrestrial Plant Exposure Assessment .....................................................................31

4. Effects Assessment ...............................................................................................31

5. Risk Characterization ..........................................................................................32

5.1 Risk Estimation ............................................................................................................32
5.2 Risk Description ...........................................................................................................32 5.3 Action Area Spatial Analysis ......................................................................................39

6. Uncertainties .........................................................................................................40

6.1 Exposure Assessment Uncertainties ...........................................................................40
6.2 Effects Assessment Uncertainties ...............................................................................42

7. Summary and Conclusions ..................................................................................42

8. References .............................................................................................................51

2

### Appendices

Appendix A Summary of Efficacy and Other Selected Open Literature Articles Appendix B Direct Effects to Identified Listed Species Appendix C Indirect Effects to Identified Listed Species Appendix D Habitat Modification to Identified Listed Species Appendix E HED Memo Appendix F Potassium Nitrate Mixture Memo Appendix G Sodium Nitrate Mixture Memo Appendix H Selected Label Restrictions a nd Instructions for the Gas Cartridges Appendix I Nitrate Verification Memo Appendix J Papers Accepted for ECOTOX for Carbon Appendix K Papers Excluded for ECOTOX for Carbon Appendix L Papers on Non-target Efficacy from ECOTOX for Carbon Appendix M Papers Rejected for ECOTOX for Carbon Dioxide Appendix N Papers Accepted for ECOTOX for Inorganic Nitrates Appendix O Papers Not Accepted for ECOTOX for Inorganic Nitrates Appendix P Other papers from ECOTOX for Inorganic Nitrates Appendix Q ECOTOX Rejection Codes Appendix R Carbon ECOTOX Spreadsheet Appendix S Inorganic Nitrate Spreadsheet Appendix T California Alameda Whipsnake Life History Appendix U California Alameda Whipsn ake Critical Habitat Designation Appendix V California Alameda Whipsnake Primary Constituent Elements Appendix W San Francisco Ga rter Snake Life History Appendix X San Joaquin Kit Fox Life History Appendix Y Spatial Analysis



### Attachments

Attachment I Supplemental Information on Standard Procedures for Threatened and Endangered Species Risk Assessmen ts on San Francisco Bay Species Attachment II Status and Life History of the San Francisco bay Listed Species Attachment III Baseline Status and Cumulative Effects for the San Francisco Bay Species Attachment IV 1996 letter concurring with EPA Region IX

1 Executive Summary

The purpose of this assessment is to evaluate pot ential direct and indirect effects arising from FIFRA regulatory actions regard ing use of carbon dioxide and use of carbon, sawdust, sodium nitrate, potassium nitrate and sulfur cartridges on non-target species (including non-listed and federally-listed species). The screening leve l assessment for the registration review was completed in accordance with procedures outlined in the Agency’s Overview Document (USEPA, 2004) and the U.S. Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS) Endangered Species Consultation Handbook (USFWS/NMFS, 1998). In

3addition to the registration review assessment a refined endangered species assessment has been completed to determine the effects of the cartridges on three listed species for which sodium nitrate and potassium nitrate were alleged to be of concern in a suit brought against the Agency ( Center for Biological Diversity (CBD) vs. EPA et al . (Case No. 07-2794-JCS): the threatened Alameda whipsnake; endangered San Francisco ga rter snake; and San Joaquin kit fox. The following uses are labeled for car bon, sawdust, sodium nitrate, potassium nitrate and sulfur rodenticide and predacide cartridges, and are considered as part of the federal action evaluated in
this assessment:

• Crops

• Gardens

• Golf Courses

• Lawns

• Noncrop

• Open Fields

• Rangelands

• Reforested areas

• Parks

• Meadows

Carbon dioxide is registered for indoor uses only.

The carbon, sawdust, sulfur, sodium nitrate a nd potassium nitrate car tridge products are pyrotechnic devices used agains t rodents and certain other mammals in burrows, including moles, pocket gophers, woodchucks, rats and No rway rats, ground squirrels, skunks, yellowbellied marmots, and prairie dogs. There is a larger gas cartridge used in dens against coyotes, red foxes and striped skunks. The cartridges are lit and rapidly inserted in the burrow or den openings, which are blocked (sealed) with soil or sod to prevent the gases from escaping. If smoke is seen escaping from other burrow openings , they should be plugged with soil or other materials. Usually more than one ca rtridge is applied for a burrow system.

Two kinds of stressors were identified in this assessment, the toxic gases released by the gas producing cartridge products, and carbon dioxide. Carbon, sawdust, sodium and potassium
nitrates and sulfur are used in pyrotechnic fumigant gas produci ng cartridge products. After the cartridges are ignited they produce gases that cause asphyxiation of the pests. The gases, not the active ingredients, are the stresso rs for these products. Not all the gases have been identified; however, it appears that multiple combustion pr oducts may be formed, including, for example, carbon monoxide, carbon dioxide, nitrogen oxide, su lfur dioxide, and nitrogen. The toxic gases displace the oxygen in the burrows and dens, crea ting an un-breathable atmosphere and causing suffocation of the target organisms.

One example of such a stressor is carbon monoxide; it combines preferentially with hemoglobin to form carboxyhemoglobin, which cannot carry oxygen, causing hypoxia (Savarie et al., 1980). Various efficacy studies (Savarie et al. 1980, Matschke et al. 1980, Fagerstone et al., 1981, Matschke & Fagerstone, 1984; Zhi & Chang, 1986; Matschke et al., 1995 and Ramey, 1995), most of which were carried out using two-ingred ient cartridges, containing sodium nitrate and

4charcoal (or carbon), were evaluate d and lead to the conclusion th at high levels of mortality are expected in burrows and dens treated with car tridges (see Appendix A for more information on those studies).

Based on the application method ( i.e ., cartridges are placed into sealed burrows/dens), the effect of the gas producing cartridges is expected to remain w ithin the appli cation site (localized as opposed to widespread). No potential transport from spray drift or run-off is expected from the use of gas producing cartridges. Furthermore, no chronic exposure is expected from the application of the gas cartridges. The gases wi ll eventually diffuse or disperse in the environment, be absorbed (entrapped) by the soil where they are metabolized by soil microorganisms or enter their elemen tal cycles (USDA 1994, cited by Ramey et al,. 1994).

Because of the fact that target or non-target species are not exposed to the active ingredients (carbon, sawdust, sodium nitrate, potassium nitrat e and sulfur), in burrows or dens, but instead are exposed to the active ingred ient’s by-products, all environmental fate and effects data requirements were waived for these active ingredient s. The gas cartridges ma y be used in crops, but they are not considered conve ntional pesticides. Because they are used inside burrows or dens, they are generally not in contact with the crops.

Carbon dioxide PC code 016601 is a fu migant used as an insecticide. It is used indoors in sites such as sealed trucks, trailers, sealed railroad cars, food handling establishments and ships. The area to be fumigated is sealed and the atmosphe re filled with a minimum of 60% carbon dioxide for four to five days. This causes the pests to die from asphyxiation. No exposure to wildlife, from the indoor use of carbon dioxide, is expected when used according to the label. Furthermore, the carbon dioxide emitted from th e use sites is not considered a threat to nontarget wildlife because the chemical is naturall y occurring in the environment. Because carbon dioxide is used indoors only, and exposure to non-target species is not expected, all the environmental fate and ecological effects data re quirements for carbon dioxide were also waived.

The effects determination assessment endpoints fo r listed species include direct and indirect effects based on toxicity information for birds, wh ich are also used as a surrogate for terrestrialphase amphibians and reptiles, as well as mammal s and insects. Direct toxic effects on the survival, reproduction, and growth as well as indirect effects, such as reduction of the prey base
or modification of habitat are considered in the as sessment. In the terrestrial habitat, indirect effects due to depletion of prey are assessed by c onsidering effects to terre strial insects, birds, small terrestrial mammals, reptiles and amphibians. Indirect eff ects due to modification of the
terrestrial habitat are characterized by available data fo r terrestrial monocots and dicots.

No aquatic or terrestrial exposur e is expected due to the indoor use of carbon dioxide. Therefore it is determined that carbon dioxide products cove red in this assessment will have No Effect on listed or non-listed species.

Furthermore, no aquatic exposure is expected fr om the outdoor use of carbon, potassium nitrate, sodium nitrate and sulfur cartridge. Therefore, th ese products are determined to have No Effect on listed and non-listed aquatic species.

5An initial assessment is conducted for Registrati on Review to determine the potential effect on non-listed species from the use of cartridges fr om outdoor terrestrial exposures. The agency determined that there was the potential for adve rse direct effects from the application of the cartridges from the combustion products to non-listed birds, mammals and terrestrial invertebrates inhabiting burrows or dens. There is also the potentia l for adverse direct effects to non-listed reptiles and amphibian s inhabiting burrows or dens based on birds being used as surrogates for those species. No direct effects fr om the use of the cartridges are expected for terrestrial plants. The determ ination is based on asphyxiation from the combustion products formed after the cartridge is ignited in the burrow or den and the burrow or den is sealed to retain the gases at the site.

A screening level assessment is also conducted under Registration Review to determine potential effects to listed species. If ther e is a determination that there is a potential for direct or indirect effects to listed species, a “may affect” determination is made. If use of the pesticides “may affect” the assessed species and/or modify desi gnated critical habitat, the best available
additional information is consid ered to refine the potential for exposure and effects, and distinguish those actions that “may affect, but are not likely to adversely affect” (NLAA) from those actions that are “likely to adversely a ffect” (LAA) endangered species and its critical
habitat.

The Agency makes a “May Affect, LAA” determ ination for listed burrowing species (birds, mammals, insects, and reptiles and amphibians using birds as a surrogate) for survival as an
acute direct effect based on as phyxiation from the combustion products. The effect from the application of the cartridges is localized to the a pplication site based on th e label instructions to seal the burrow or den following the applicati on. Supporting evidence is based on habitat and diet life history information (Nat ureServe, 2009) for taxa representi ng listed species identified in Appendix B. A “no effect” determination is made for those species not identified in the Appendix B.

Additional supporting information is provided from a 1993 Biologica l Opinion (BO) as well as memos from the USFWS indicating jeopardy to terre strial mammals and reptiles with specific reasonable and prudent alternatives (RPAs) fo r each species addressed in the BO. The BO identified RPAs for 17 specific species. This information was included on two labels, the Gas Cartridge and the Large Gas Cartridge. Six of those identified listed species were also included on three labels (Dexol Gopher Gasser, Revenge Smoke Bomb and SMOKE’em). One label does not include specific listed species information (Giant Destroyer).

The BO also indicated that even with implementa tion of the alternatives, there was still risk for the San Joaquin kit fox, Point Ar ena mountain beaver, Fresno kanga roo rat, giant kangaroo rat, and Tipton kangaroo rat resulting in an unquantifiable level of incidental take . The current labels
reflect the need to limit use in the habitat of the Bl ack-footed ferret, San Joaquin kit fox, Utah prairie dog, blunt-nosed leopard liz ard, Eastern indigo snake and dese rt tortoise. Additionally, a
letter from the US Fish and Wildlife Serv ice to EPA’s Region 9 office (November 1, 1996) indicated that the California Depa rtment of Pesticide Regulation’ s (Cal DPR) endangered species bulletins that address the potential effects of burrow fumigants to those species addressed in the 1993 BO, including the SFGS and SJKF, were adequate and could be substituted for the RPAs as

6described in the BO. Therefore, the species for which labeling was ch anged relative to the 1993 BO and those covered by the Cal DPR bulletins which also were addres sed in the 1993 BO are adequately protected at this time from potentia l effects of the burrow fumigants being assessed here. Nonetheless, during consultation with th e US Fish and Wildlife Service on other species potentially affected, EPA will confirm that the m easures in place remain adequate and that the ranges of these species have remained consta nt since the 1993 BO and the 1996 letter to EPA Region 9.

Potential indirect effects in the form of reducti on in prey for listed spec ies also resulted in a “May Affect, LAA” determination for birds, mammals, reptiles and amphibians based on asphyxiation from the combustion products. The indi rect effects from cartridge application are not limited to species inhabiting burrows or dens because some prey are included in the diets of listed species that do not inhabit burrows or dens. Supporting evidence is based on diet life history information (Nature Serve, 2009) for ta xa representing listed species consuming prey with burrow/den habitats as reported by USFWS which are iden tified in Appendix C. A “no
effect” determination is made for those species not identified in the Appendix C.

Indirect effects also include potential habita t modification. Habitat modification is based on reduction in prey as well as cha nges in habitat used for shelter or reproduction for species with designated critical habitat. The national level determination provides screening level results for taxa based on potential effects to identified listed species, which includes if a critical habitat has been designated for that species by USFWS in Appendix D. There is a “Habitat Modification” determination for listed birds, mammals, reptil es and amphibians based on reduction in prey based on a conservative estimate of 100% mortality from the combustion products as well as
reduction in shelter. Shelter can be reduced due to sealing the burrow or den entrances following application of the cartridges, especially for species that use other animal burrows or dens rather than creating their own burrows or dens. Habita t Modification for terrestrial invertebrates is based on limiting access to the burrows or dens after the pesticide is applied through sealing entrances. The Habitat Modification for plants is based on potential for reduction in seed dispersal. Because mammals may transport seeds in their fur, dispersal may be reduced due to the number of mammals available in a geographi c area. Supporting eviden ce is based on habitat life history information (Nature Serve, 2009) for ta xa representing listed species consuming prey with burrow/den habitats as reported by USFWS which are iden tified in Appendix D

. A “no
effect” determination is made for those species not identified in the Appendix D.

These determinations are based on lines of evid ence using the best avai lable information. The screening level determinations are summarized for Registration Review in Tables 1.1 for nonlisted species and in Table 1.2 for the listed specie s. The determinations for the three species for which refinements have been made are presented in Table 1.3, and the effects determination for designated critical habitat for one species for wh ich refinements have been made, is provided in
Table 1.4.

7Table 1.1. Potential Direct Effects on Non- Listed Species Inhabiting Burrows and Dens for the Use of Carbon, Sawdust, Pota ssium Nitrate, Sodium Nitrate and Sulfur Cartridges

Species Assessment Endpoint Description of Results of Risk Estimation

Burrowing Birds

Burrowing
Mammals

Burrowing Reptiles

Burrowing Amphibians

Burrowing

Terrestrial

Invertebrates Survival There is a potential for acute dir ect adverse effects on burrowing species based on asphyxiation from the combustion products at the site of application.

81.2 Effects on Listed Species for the Use of Carbon, Sawdust, Potassium Nitrate, Sodium Nitrate and Sulfur Cartridges

Species Assessment Endpoint Effects

Determination Description of Results of Risk Estimation

Direct Effects

Terrestrial (Juveniles and adults)

Burrowing
Birds

Burrowing
Mammals

Burrowing Reptiles

Burrowing Amphibians

Burrowing
Terrestrial
Invertebrates Direct Effects
Survival of
individuals
via direct
effects on
terrestrial organisms May Affect

LAA The determination for acute direct effects is based on 100% mortality from asphyxiation based on the combustion products following application.

Indirect Effects

Birds

Mammals

Reptiles

Amphibians Survival of
individuals
via reduction of prey ( i.e., birds,
terrestrial mammals, reptiles,
terrestrial phase amphibians
and terrestrial invertebrates) May Affect

LAA The determination for acute indirect effects is due to an inability to measure the effect for reduction in prey based on asphyxiation from the combustion products. The reduction inprey may affect both burrowing and nonburrowing listed species consuming animals

with burrow/den habitats.

91.2 Effects on Listed Species for the Use of Carbon, Sawdust, Potassium Nitrate, Sodium Nitrate and Sulfur Cartridges

Species Assessment Effects Endpoint Determination Description of Results of Risk Estimation

Birds

Mammals

Reptiles

Amphibians

Terrestrial

Invertebrates There is a “Habitat Modification” based on a reduction in prey from asphyxiation for both burrowing and non-burrowing species.

There is a “Habitat Modification” determination for burrowing species based on a reduction in cover/shelter. Use of the pesticides in cartridge products results in reduced access to burrows for shelter or reproduction.

Terrestrial

Plants Survival of endangered species via

effects on habitat ( i.e.,

reduction in prey, shelter, riparian vegetation) Habitat Modification

There is a habitat modification determination for terrestrial plants based on the potential for reduction in seed dispersal.

10Table 1.3 Effects Determination Summary for Effects of Potassium and Sodium Nitrate Cartridges for Three Listed Species
Species Effects
Determination Basis for Determination 1

Potential for Direct Effects Terrestrial-phase (Juveniles and Adults) :

Habitats for the snake include shrub communities and adjacent habitats of grassland, savanna and oak-bay woodland. The most common types of retreat site in both the grassland and scrub
communities are small rodent burr ows and rock crevices, with brush piles, deep soil crevices and debris piles also used for
cover/shelter. The determination fo r acute direct effects is based on 100% mortality from asphyxiation based on the combustion products following application, if applied to a burrow in which the snake is residing during application.

Potential for Indirect Effects Alameda Whipsnake ( Masticophis

lateralis euryxanthus ) (AW) May Affect, Likely to Adversely Affect (LAA)

Terrestrial prey items, riparian habitat

There is an “LAA” determination fo r acute indirect effects due to prey reduction for the AW consuming lizards, snakes and small mammals that may inhabit burrows. The prey may be present at the site of application, which results in mortality for the prey.

Potential for Direct Effects Terrestrial-phase (Juveniles and Adults) :

The SFGS uses densely vegetated ponds near open hillsides where they can sun themselves, feed, and find shelter in rodent burrows. Rodents are targets for nitrate cartridges. The determination for acute direct effects is based on 100% mortality from asphyxiation based on the combustion products following application if applied to a burrow in which the snake is residing during application. US FWS has indicated measures put in place by Cal DPR are adequate protection for this species relative to uses of burrow fumigants.

Potential for Indirect Effects San Francisco
Garter Snake ( Thamnophis

sirtalis

tetrataenia ) (SFGS) May Affect, Not Likely to Adversely Affect (NLAA)

Terrestrial prey items, riparian habitat

There is an “NLAA” determinatio n for acute indirect effects due to prey reduction. The main diet of adult SFGS consists of California Red-Legged Frog ( CRLF), which are listed as a threatened species (USFWS, 1985 and 2007). CRLFs also use

small mammal burrows and moist l eaf litter as habitat, and might be present at the time of application. US FWS has indicated measures put in place by Cal DPR are adequate protection for this species relative to uses of burrow fumigants.

11Table 1.3 Effects Determination Summary for Effects of Potassium and Sodium Nitrate Cartridges for Three Listed Species
Species Effects Basis for Determination 1

Determination

Potential for Direct Effects Terrestrial-phase (Juveniles and Adults) :

The fox inhabits a variety of ha bitats, including grasslands, grazed grasslands, shrublands, meadows, and areas of row crops, orchards and vineyards (East Contra Costa County HCP/NCCP, 2006). Although kit foxes may dig their own dens, they also modify and use those constructed by other animals (ground squirrels, badgers, and coyotes). Coyotes and ground squirrels are both target pests. The determination for potential acute direct effects is based on 100% mortality from asphyxiation based on the combustion products following application at the application site. US FWS has indicated measures put in place by Cal DPR are adequate protection for this species relative to us es of burrow fumigants.

Potential for Indirect Effects San Joaquin Kit Fox ( Vulpes

macrotis mutica ) (SJKF) May Affect, Not Likely to Adversely Affect (NLAA)

Terrestrial prey items, riparian habitat

There are potential acute indirect effects due to prey reduction for the SJKF consuming small mammals such as kangaroo rats, pocket mice, California ground squirrels and insects that may inhabit burrows. Some of the small mammals may also be target pests, such as ground squirrels. The prey may be present at the site of application, which results in mortality of the prey. However, USFWS has indicated measures put in place by Cal DPR are adequate protection for this species relative to uses of burrow fumigants.

1 For more detailed information on the distribution, habitat requirements, and life history information of the assessed listed species, see Attachment II.

121.4. Effects Determination Summary for the Critical Habitat Impact Analysis
Designated
Critical Habitat
for: Effects
Determination Basis for Determination 1

Almeda WhipSnake (AW)
Habitat
Modification Lines-of-evidence indicate potential adverse effects for reduction in prey for the AW consuming species inhabiting burrows.

The PCEs for the AW include mammal burrows as habitat. Because the application method involves closing the burrow openings after inserting the cartridge, there would be a reduction in available shelter/cover.

1 For more detailed information on the distribution, habitat requirements, and life history information of the assessed listed species, see Attachment II.

Given the LAA determination for the CAW and pot ential modification of designated critical habitat for the CAW, a description of the baselin e status and cumulative effects for the CAW is provided in Attachment III.

EPA previously requested modification of the la bels for the Gas Cartridge and the Large Gas Cartridge based on conclusions fr om the Biological Opinion (1993) . That BO identified 17 listed species with specific mitigation for each such as time of use and geographic boundaries. In addition, memos from USFWS indicated risk to identified mammals and reptiles and included mitigation specific to the six identified species. Based on those memos, six listed species were included on labels for Dexol Gopher Gasser, SMOKE’em, and Revenge Smoke Bomb. Those modified labels provide the basi s for the current assessment.

Based on the conclusions of this assessment, incl uding additional listed species identified and the need to review geographic boundaries for current and previously iden tified listed species,
consultation will be reinitiated with the U. S. Fi sh and Wildlife Service under Section 7 of the Endangered Species Act. A screening list of endangered species with the potential to be adversely impacted by potassium nitr ate, sodium nitrate, carbon, sawdust and sulfur cartridges is provided in Appendices B-D. A ‘no effect” determination has been made for all other listed species and their critical habitat, not identified on the Appendices B-D.

2. Problem Formulation

The purpose of the problem formulation is to pr ovide the foundation and a strategic framework for the ecological risk assessment. It identifies the important components of the problem and
focuses the assessment on the most relevant life history stages, habita t components, chemical properties, exposure routes, and endpoints. As such, it articulates the purpose and objectives of the risk assessment, evaluates the nature of th e problem, and provides a plan for analyzing the data and characterizing the risk (USEPA, 1998). Th e structure of this risk assessment is based on guidance contained in U.S. EPA’s Guidance for Ecological Risk Assessment (USEPA, 1998).

132.1 Purpose

This document supports EPA’s registration review of the subject pesticides. This assessment evaluates the potential direct e ffects on non-listed species and direct and indire ct effects on listed species arising from FIFRA regul atory actions regarding the use of carbon, sawdust, potassium nitrate, sodium nitrate and sulfur in fumigant gas producing cartridge products. This assessment also addresses potential effects of three species allege d to be of concern in a suit brought against EPA ( Center for Biological Diversity (CBD) vs. EPA et al . (Case No. 07-2794-JCS)): the Alameda whipsnake, the San Francisco garter snake and the San Joaquin kit fox. The Alameda whipsnake ( Masticophis lateralis euryxanthus ) was listed as threatened on December 5, 1997 (62 FR 64306) by the U.S. Fish and Wildlife Service (USFWS ) (USFWS, 1997 and Westphal, 1998). The San Francisco Garter Snake (SFGS) ( Thamnophis sirtalis tetrataenia ) was listed as endangered on March 11, 1967 (32 FR 4001; USFWS 1967) by the U.S. Fish and Wildlife Service (USFWS) and was grandfathered under the Endangered Spec ies Act (ESA) when it was signed into law in 1973. The San Joaquin kit fox ( Vulpes macrotis mutica ) was listed as endangered on March 11, 1967 (32 FR 4001) by the U.S. Fish and Wild life Service (USFWS) (USFWS, 1967). These
assessments do not include the use of carbon dioxid e as an indoor fumigant. They do not include sulfur uses other than the gas cartridge use. In 1991, the Reregistration Eligibility Document (RED) for the Case No. 4052 (List D), which incl udes both inorganic nitrates and nitrites was issued. By the time of the RED issuance (1991) , no nitrite products were registered, and no evaluation of nitrite products was performed; for the same reason, no evaluation of nitrite products is currently needed.

Analyses of effects to listed species are conduc ted. In accordance with the Overview Document (US EPA, 2004), provisions of the ESA, and the Services’ Endangered Species Consultation Handbook, the assessment of effects associated with registrations of carbon, sawdust, potassium nitrate, sodium nitrate and sulfur cartridges are based on an action ar ea. It is noted that the action area for a national-level FIFRA regulatory decision associated with a use of carbon, sawdust, potassium nitrate, sodium nitrate and sulfur may potentially involve numerous areas throughout
the United States and its Territories. The acti on area for the three species for which refined
assessments were conducted is limited to California.

As part of the “effects determination,” one of the following three conc lusions will be reached regarding the potential use of carbon, sawdust, po tassium nitrate, sodium nitrate and sulfur in
accordance with current labels:

• “No effect”;

• “May affect, but not likely to adversely affect”; or

• “May affect and likely to adversely affect”.

Designated critical habitat (if a pplicable) identifies specific ar eas that have the physical and biological features, (known as primary constituent elements or PCEs) essential to the conservation of listed species.

If the results of initial screening-level assessment methods show no direct or indirect effects (no LOC exceedances) upon individual listed species or upon the PCEs of the species’ designated critical habitat (if applicable), a “no effect” determination is made for use of carbon, sawdust,

14potassium nitrate, sodium nitrate and/or sulfur as it relates to this species and its designated critical habitat. A “no effect” determination is made for those species not identified in the Appendices B-D.

If, however, potential direct or i ndirect effects to individual speci es are anticipated or effects may impact the PCEs of the species designated cr itical habitat, a preliminary “May Affect” determination is made for the FIFRA regulator y action regarding the chemical(s). If a determination is made that the use of carbon, sa wdust, potassium nitrat e, sodium nitrate and sulfur within the action area(s) associated with a species “May Affect” this species or its designated critical habitat, addi tional information is considered to refine the potential for exposure and for effects to the species a nd other taxonomic groups upon which they depend ( e.g., aquatic and terrestrial verteb rates and invertebrates, aquatic plants, riparian vegetation, etc.). Based on the refined information, the Agency uses the best available information to distinguish those actions that “M ay Affect, but are Not Likely to Adversely Affect” from those actions that “May Affect and are Likely to A dversely Affect” a species or the PCEs of its designated critical habitat. This information is summarized as taxa and presented as part of the
Risk Characterization in Section 5 of this document. A summary of species with LAA determinations can be found in Appendices B and C. Species with poten tial habitat modification are summarized in Appendix D. The determinations for the refined assessment for the three species are presented in the executive summary and the conclusion, section 7.

The Agency believes that the analysis of direct and indirect effects to individual species provides the basis for an analysis of poten tial effects on the designa ted critical habitat. Carbon, sawdust, potassium nitrate, sodium nitrate and sulfur cartridges may directly impact living organisms within the action area (defined in Section 2.5). Cr itical habitat analysis for these six chemicals is limited in a practical sense to those PCEs of critic al habitat that are biological or that can be reasonably linked to biological ly mediated processes ( i.e. , the biological resource requirements for the listed species a ssociated with the critic al habitat or important physical aspects of the habitat that may be reasonably influenced thro ugh biological processes) . Activities that may modify critical habitat are those that alter the PCEs and appreciably diminish the value of the
habitat. Evaluation of actions related to use of carbon, sawdust, potassium nitrate, sodium nitrate and sulfur that may alter the PC Es of a species’ critical habitat form the basis of the critical habitat impact analysis.

2.2 Scope

The end result of the EPA pesticide registration process ( i.e. , the FIFRA regulatory action) is an approved product label. The label is a legal document that stipulates how and where a given pesticide may be used. Product labels (also know n as end-use labels) de scribe the formulation type ( e.g. , liquid, granular or cartridg e), acceptable methods of app lication, approved use sites, and any restrictions on how applications may be conducted. Thus, the use or potential use of carbon, sawdust, potassium nitrate, sodium nitrate, and sulfur car tridges in accordance with the approved product labels is “the action” releva nt to this ecologi cal risk assessment.

Carbon (PC Code 016001), including carbon as saw dust, potassium nitrate (PC Code 076103 ), sodium nitrate (PC Code 076104) and sulfur (PC Code 077501) used as rodenticide and

15predacide fumigants in gas cartridges include multip le active ingredients. This single assessment evaluates all these chemicals. The six register ed gas cartridge products include various active ingredients formulated as mixtures (refer to Table 2.1). SMOKE’em (4-463) includes potassium nitrate, sulfur and sawdust as active ingredients. Dexol G opher Degasser (192-49) and Revenge Rodent Smoke Bomb (9086-4), both include pota ssium nitrate, sulfur and carbon as active ingredients. The Giant Destroye r (10551-1) includes sodium n itrate, sulfur and carbon. The Large Gas Cartridge (56228-21) and the Gas Cartridge (56228-2) , both include sodium nitrate and carbon as active ingredients.

2.3 Previous Assessments

2.3.1 Previous Assessments

In 1991, the Agency issued Reregistration Elig ibility documents for carbon dioxide and carbon, sodium nitrate and potassium nitrate, and sulfur cartridges that serve as the basis for this
assessment. At the time sawdust as an active i ngredient was not included in the document. It was concluded that, for these active ingredients, application of the ca rtridges to burrows (subsurface) precludes exposure to avian and aqua tic organisms. However, organisms that live in burrows and dens, including listed species, ma y be impacted. For carbon dioxide, with only indoor uses, the Agency concluded that exposur e to non-listed or listed species was unlikely.

The current labels for the Gas Cartridge and th e Large Gas Cartridge reflect proposed mitigation measures to reduce potential list ed species effects identified in the 1991 Reregistration Eligibility Document (RED).

The problem formulation for Registration Re view was submitted March 18, 2008. There have been no additional fate or ecological studies reviewed since the problem formulation was completed. No major changes have been made to the Problem Formulation; however, the conceptual model was modified to include indir ect effects to non-target species and additional use information was included. The analysis plan submitted in the problem formulation remains
the basis for this assessment.

2.3.2 Literature Information and Efficacy Studies

A brief summary of various articles found in the literature is presented in Appendix A. The summary of the articles presents information on the effectiveness (or efficacy) of the gas cartridges (most of the information referred to cart ridges containing carbon and sodium nitrates).
Where articles contained inform ation for methods other than the cartridges, emphasis was put into the cartridges, and information on other methods was include d only if it related to the use of cartridges. The cartridge litera ture search provided useful info rmation about their use, methods to assess their efficacy, and factors that affect the efficacy of the cartridges. The following are example articles that presented information about efficacy: Savarie et al., 1980; Matschke et al., 1980,; Fagerstone et al., 1981; Matschke & Fagerstone, 1984; Zhi & Chang, 1986; Matschke et al., 1995 and Ramey, 1995. Using a variety of methods to quantize the efficacy, it was variable. According to various of the artic les, the USEPA requirement of efficacy, and the minimum level of mortality desired for the cartridge products is 70%; but for certain species, this level of

16mortality was not achieved ( e.g. for badgers, see Ramey 1995 in Appendix A), and such species were not claimed as target species in the labels for the cartridge products.

2.4 Stressor Source and Distribution

2.4.1 Nature of the Chemical Stressor

The toxic gases released in the gas producing cartridge products were identified as the stressors in this assessment. Carbon, sawdust, sodium an d potassium nitrates and sulfur are used in pyrotechnic fumigant gas produci ng cartridge products. After th e cartridges are ignited they produce gases that cause asphyxiation of the pests. The gases, not the active ingredients are the stressors for these products. Not all the gases have been identified; however, it appears that multiple combustion products are formed, in cluding as examples, carbon monoxide, carbon dioxide, sulfur dioxide and nitrogen gas. Th e gases displace the oxygen in the burrows, creating an un-breathable atmosphere and causing suffocati on of the target organisms. An example of a possible combustion reac tion (Magran, no date, as cited by Savarie et al , 1980) is:

4C +2NaNO 3 → 3CO (g) + Na 2 CO 3 + N 2 (g)

All these compounds are consider ed relatively non-toxic, ex cept for carbon monoxide. In mammals and other organisms, it causes hypoxia (see Section 2. 4 .3).

2.4.2 Environmental Transport Mechanisms

Based on the application me thod, the effect of the gas producing cartridges is expected to remain at the application site (locali zed as opposed to widespread). The primary transport mechanism for the cartridges combustion by-pro ducts is expected to be diffusi on. The soils are expected to absorb or entrap part of the gases produced, wh ere they are metabolized by soil microorganisms or enter their elemental cycles, while the remai nder may be slowly lost to the environment (see USDA 1994, as cited by Ramey et al. 1994). Generally, the effect expected from exposure to these gases will be acute and it will be mortalit y. Based on the exposure expected from the gas cartridges, no modeling is require d (see Section 3.2). The efficacy studies support a conservative assumption of 100% mortality from exposure to th ese gases (see Appendix A for further details). No potential transport from spray drift or run-o ff is expected from the use of gas producing cartridges because they are used in sealed burrows.

2.4.3 Mechanism of Action

Gas cartridges containing carbon, sawdust, potassi um nitrate, sodium nitrate and sulfur are fumigants for outdoor use. The release of toxic gases ( e.g. carbon monoxide and sulfur dioxide) after ignition in sealed burrows induces asphyxiation of organisms that live in burrows or dens. One example of such toxic gas is carbon monox ide [CO (g)]. It combines with hemoglobin (preferentially over oxygen), to form carboxyhemoglobin (prefere ntially over oxyhemoglobin). The hemoglobin is then unable to transport oxygen, causing hypoxia ( i.e. the body is deprived of an adequate supply of oxygen), and eventuall y, death. A memo dated March 6, 2008 from the

17Human Health Effects Division of EPA supports the mode of action (Appendix E) (see also
Savarie et al., 1980).

2.4.4 Use Characterization

Analysis of labeled use information is the critical first step in evaluating the federal action. The current labels for carbon, sawdust, potassium nitr ate, sodium nitrate a nd sulfur gas cartridge products represent the FIFRA regul atory action. Therefore, labeled use and/or app lication rates specified on the label form the basis of this a ssessment. The assessment of use information is critical to the development of the action area a nd selection of appropriate modeling scenarios and inputs.

Table 2.1 summarizes information derived from the six labels for the gas cartridge products. The table provides product names, percentages of active ingredients, target sp ecies and use sites for
the labels considered in this assessment. It is noted that the gas cartrid ges may be used in crop sites; however, they are not conve ntional pesticides. Ge nerally they are conf ined to the treated
burrows or dens and are not in close contact w ith the crops. The active ingredients in the gas cartridges are not restricted use pesticides. Ca rtridges may not be used in or around buildings.

Table 2.1. Cartridge Products Containing Carbon or Sawdust plus Sodium or Potassium
Nitrate and Sulfur
Product Name, Reg No. Active Ingredients % Target Species;
Use Areas

SMOKE’em

4-463 Potassium nitrate 46.2%
Sulfur 34.8%
Sawdust 8.7% Woodchucks, ground squirrels; Open fields, non-crop areas

Dexol Gopher Degasser

192-49 Potassium nitrate 45.0%
Sulfur 45.0%
Carbon 8.0% Gophers, ground squirrels; Lawns, golf courses, gardens, rangeland

Revenge Rodent
Smoke Bomb

9086-4 Potassium nitrate 38.8%
Sulfur 39.4%
Carbon 12.5% Gophers, woodchucks, rats, skunks, ground squirrels; Lawns, golf courses, non-crop areas, rangeland, meadows, reforested areas, open fields, parks The Giant Destroyer

10551-1 Sodium nitrate 46.2%
Sulfur 34.8%
Carbon 8.7% Gophers, moles, woodchucks, rats, skunks, ground squirrels; Lawns, golf courses, non-crop areas, rangeland, meadows, reforested areas, open fields Large Gas Cartridge

56228-21 Sodium nitrate 53.0% Carbon (Charcoal) 28.0% Coyotes, red foxes, striped skunks; In dens only in rangeland, crop and non-crop areas Gas Cartridge

56228-2 Sodium nitrate 53.0% Carbon (Charcoal) 28.0% Woodchucks, yellow bellied marmots, ground squirrels, black tailed prairie dogs, white tailed prairie dogs, Gunnison prairie dogs; Open fields, non-crop areas, rangeland, reforested areas, lawns, golf courses

Although all six formulated products are mixtures, the Agency does not routinely include, in its risk assessments, an evaluation of mixtures of active ingredients. There is no data for individual active ingredients and no data for mixtures cont aining carbon, nitrates or sulfur as active

18ingredients. Summaries of data available for the cartridge mixtur es are presented in Appendices
F and G.

Selected label restrictions are included in A ppendix H. There are two common elements across the labels. One is that the use of the cartridges is restricted to active sites, where target organisms are present. For example, the Enviro nmental Hazards section of the labels for Dexol Gopher Gasser, the Gas Cartridge, the Large Gas Cartridge, and Revenge Rodent Smoke Bomb, says: “This product is highly toxic to wildlife. Check all burrows fo r signs of non-target species. If present, do not treat burrows.” Therefore, a ccording to the instructi ons, the sites are required to be inspected prior to cartri dge use. The other element is that all six labels require the entrance(s) to the burrow or den to be sealed at the time of application of the cartridge.

However, there are also differences across the labels. Five of the six labels are for burrow applications. The only common target species iden tified in all five burrow labels is the ground squirrel. The sixth label identifie s coyotes, red foxes and striped s kunks as target organisms, in dens. A verification memo from the Registra tion Division of EPA (2/19/2010) indicates no nitrate products have been cancelled or any rate changes approved as part of the reregistration process (Appendix I).

The Screening Level Usage Analysis (SLUA) wa s verified for these chemicals. The SLUA provides the average annual pounds of pestic ide applied for each agricultural crop ( i.e. for the states surveyed, not for the entire U.S.). A ccording to the SLUA for sodium nitrate, dated 6/15/07, it appears that crops of major use for th e chemical are almonds, kiwifruit, nectarines, olives, pistachios, and prunes and plums. In each case, <500 lb of active ingredient were used. However, it is indicated that ≥ 95% of the U.S. acres that have this gas cartridge use are in California. For potassium nitrate, the SLUA, also dated 6/15/07, lists almonds, nectarines, pistachios and prunes and plums as the crops of interest, but <500 lb ac tive ingredient were utilized. As in the previous case for sodium nitrate, it is indicated that ≥ 95% of the U.S. acres that have potassium nitrate gas cartridge use are in California. SLUA data sources include: USDA-NASS (United States Depa rtment of Agriculture's National Agricultural Statistics Service); Private Pesticide Ma rket Research, NPUD 2002 (Nationa l Pesticide Use Database) of the CropLife America Foundation and California DPR data. Results reflect amalgamated data releasable to the public. Given th ese facts, and provided that a ll the cartridge products contain either sodium nitrate or potassium nitrate, the usage in California becomes particularly relevant.

Although no typical usage data (numbe r of applications, “rate” or interval between applications) is available for carbon or sawdust, the Agency ’s Biological and Econom ic Analysis Division (BEAD) provided a use summary, based on the Calif ornia’s Department of Pesticide Regulation Pesticide Use Reporting (CDPR PUR) database . The California Department of Pesticide Regulation’s Pesticide Use Reporting database provi des a census of pesticide applications in the state (Table 2.2-2.3). See http://www.cdpr.ca.gov/docs/pur/purmain.htm . Agricultural uses reported in the CDPR PUR databa se include applications to pa rks, golf courses, cemeteries, rangeland, pastures, and along roadsi de and railroad rights-of-way. For the gas cartridges, the
labels restrict the uses in residential sites.

Publicly available data from the California De partment of Pesticide Regulation was used to produce the following table ( 2.2 ) outlining the pounds of carbon used for cartridges in California

19over the three most recent years available at th e time the data was gathered (2003-2005). The major “crop/ areas” for carbon were vertebrate c ontrol, right-of-way a nd landscape maintenance.

20Table 2.2. Carbon Usage

Crop/Area 2003 Lbs. Applied 2004 Lbs Applied 2005 Lbs. Applied

ALMOND 40 29 17

CHERRY 4 1

GRAPE 30

KIWI 0.1

LANDSCAPE MAINTENANCE 283 145 110

LEMON 1

NURSERY OUTDOOR TRANSPLANTS 2 3

NURSERY GREENHOUSE

TRANSPLANTS 2

NECTARINE 3 OAT (FORAGE - FODDER) 2

PEAR 0.1 2

PISTACHIO 28 18

RANGELAND 3

REGULATORY PEST CONTROL 9 16 42

RESEARCH COMMODITY 0.01 0.03

RIGHTS OF WAY 376 488 570

STRUCTURAL PEST CONTROL 3 1 2

UNCULTIVATED AG 9

VERTEBRATE CONTROL 1,296 345 224

WALNUT 4 11 37

Chemical Total 2,051 1,047 1,056

Prepared by: Jenna Carter 7/31/07

Publicly available data from the California De partment of Pesticide Regulation was used to produce Table 2.3, outlining the pounds of sawdust us ed in California over the three most recent years. Only 0.143 to 1.417 lbs of sawdust were us ed from 2003 to 2005 in California, and they were mostly used for landscape ma intenance and vertebrate control.

Table 2.3. Sawdust Usage

Crop/Site 2003 Lbs. Applied 2004 Lbs. Applied 2005 Lbs. Applied

CHERRY 0.11

LANDSCAPE

MAINTENANCE 0.4956 0.88 0.011

STRUCTURAL PEST

CONTROL 0.12

21VERTEBRATE CONTROL 0.5412 0.5368 0.022

Chemical Total 1.1568 1.4168 0.143
Prepared by: Jenna Carter 8/01/07

For sulfur containing cartridges, the California Department of Pesticide Regulation (CDPR) use
information data indicate that the use for “v ertebrate control” in the period of 2003 to 2005 ranged from 453 to 4418 lbs. Sulfur has uses other than cartridges; therefor e, the usage table is
not included.

It appears that the acreage treate d with gas cartridges is usually relatively small, as suggested by an informational sheet from the Montana Department of Agriculture. Acco rding to the leaflet, available on the internet, fumigants, such as ca rtridge products, “are effective tools for follow up of poison bait applications.” It further says that, “Burrow fumigants can also be used as a primary control technique although cost of materi als and labor generally restrict their use to small acreages or sparse populations.” H ygnstrom & VerCauteren (2000) evaluated the effectiveness and cost of five burrow fumigants used to manage black-tailed prairie dogs: methyl bromide, chloropicrin, methyl bromide-chlor opicrin mixture, aluminum phosphide and gas cartridges. (Note: At the pres ent time, methyl bromide and chlo ropicrin are not registered for this use.). No difference in effi cacy was found among treatment methods ( ≥ 95% reduction); but costs of aluminum phosphide and gas cartridges we re around twice that for the other fumigants.

2.5 Action Area

The definition of action area requi res a stepwise approach that begins with an understanding of
the federal action. The federal action is defi ned by the currently labeled uses for carbon, sawdust, potassium nitrate, sodium nitrate and sulf ur cartridges.

For a nationwide risk assessment conducted under Registration Review, the action area will encompass the entire United States and its territori es. The purpose of defining the action area as
the entire United States and its territories is to ensure that the initial area of consideration encompasses all areas where the pesticid e may be used now and in the future.

It is important to note that the nationwide action area does not imply that di rect and/or indirect
effects and critical habitat modifi cation are expected to or likely to occur over the full extent of the action area, but rather to identify all listed spec ies and critical habitat that may be potentially affected by the action. The Agency will use more rigorous analysis including consideration of available land cover, toxicity data and exposur e information to determin e areas where individual listed species and designated cr itical habitat may be affect ed or modified via endpoints associated with survival, growth or reproduction.

222.6 Ecosystems Potentially at Risk

The terrestrial ecosystems potentially at risk for the use of the cartridges are widespread, but are geographically limited following ap plication. The gas cartridges may be used in sealed burrows in such areas as open fields, non-crop areas, rang eland, reforested areas, lawns and golf courses. Also, they may be used in dens, in rangela nd, crop and non-crop areas. However, these uses result in limited exposure to wildlife off the burrows or dens. Areas adjace nt to the treated site could include cultivated fields, fencerows and hedgerows, meadows, fallow fields or grasslands, woodlands, riparian habitats and other uncultivated areas. Becaus e the cartridges are applied in burrows and dens that are sealed, minimal exposur e is expected away from the burrows, and in areas adjacent to the treated field. Generally th e ecosystems at risk consist of the burrow (or den) system only.

The sealed burrow application of carbon, sawdust, sodium nitrate, potassium nitrate, and sulfur gas cartridge is not expected to resu lt in exposure to aquatic ecosystems.

2.7 Receptors

The receptor is the biological entity that is exposed to the stressor (USEPA, 1998). Various types of receptors, including birds, rodents and other small mammals, reptiles, amphibians and terrestrial invertebrates, may inhabit burrows and may be e xposed to carbon, sawdust, potassium nitrate, sodium nitrate and sulfur products applied in the form of gas cartridges. These gas cartridges have outdoor uses only.

As indicated earlier, the pest sp ecies are not exposed to the activ e ingredients in gas cartridges, but rather to the products of their combustion. The cartridge a pplication is subsurface into burrows, so exposure to aquatic organisms and most birds or ma mmals (those that do not inhabit burrows) is not anticipated. Any organism inhabiting or present in burrows (or dens) at the time of pesticide application may be exposed to the stressors, a nd impacted by the cartridges. Therefore, there are potential dire ct impacts to non-listed species a nd direct and indirect effects to listed species.

Consistent with the process described in the Overview Document (USEPA, 2004) risk assessments use a surrogate species approach in its evaluation of pes ticides such as carbon, sawdust, potassium nitrate, sodium nitrate and sulfur cartridges. Data from surrogate test species are intended to be representative of broad taxonomic groups, and are used to extrapolate potential effects on a variety of species (receptors) included under these taxonomic groups. Although all toxicity data requirements for the ga s cartridge use of carbo n, sawdust, potassium nitrate, sodium nitrate and sulfur have been waived, additional li nes of evidence are available to support conclusions.

2.8 Assessment Endpoints and Measures of Ecological Effect

Assessment endpoints are defined as “explicit expressions of the actual envir onmental value that is to be protected” (USEPA, 2004). Defining an assessment endpoint involves two steps: 1) identifying the valued attributes of the environm ent that are determined to be at risk; and 2)

23operationally defining the assessment endpoint in terms of an ecological entity ( i.e ., a community of burrowing animals) and its attributes ( i.e ., survival and reproduction). Therefore, selection of the assessment endpoints is ba sed on valued entities ( i.e ., ecological receptors), the ecosystems potentially at risk, the migration pathways of pe sticides and the routes ecological receptors are exposed to pesticide-related contamination. The selection of clearly defined assessment endpoints is important because they provide direction and boundaries in the risk assessment for addressing risk management issues of concern. Changes to assessment endpoints are typically estimated from the available toxicity studies, wh ich are used as the measures of effects to characterize potential ecological risks associated with exposure to pesticides such as carbon, sawdust, potassium nitrate, sodium nitrate and su lfur. For this assessment, several efficacy and other publicly available articles were evaluated. In addition, the mode of action of the cartridge products was taken into consider ation when determining assessm ent endpoints. Based on this information, the assessment endpoint is survival . Furthermore, a conservative assumption of 100% mortality is assumed, for organism s inhabiting treated burrows or dens.

Registrant submitted ecological toxicity data were waived for carbon, sawdust, potassium nitrate, sodium nitrate and sulfur based on gas cartridge us e patterns due to lack of any direct adverse effects on non-target species asso ciated directly to the active ingredients of the cartridge products. No additional data are requir ed to determine relevant endpoints.

2.8.1. Assessment Endpoints

Assessment endpoints for non-listed and listed species incl ude direct effects on the survival as well as indirect effects, such as reduction of the prey base from a reduction in survival from the combustion products. In addition, potential modi fication of critical habitat is assessed by evaluating potential effects to PCEs, which are components of the habita t areas that provide essential life cycle needs, those components nece ssary for the survival, growth and reproduction of the listed species. Each assessment endpoint requires one or more “measures of ecological effect,” defined as changes in the attributes of an assessment endpoint or changes in a surrogate entity or attribute in response to exposure to a pesticide.

The only assessment endpoint for direct effects is survival. Due to a conservative estimate of 100% mortality from the combustion products expect ed at the site of application, no toxicity
studies will be used in this a ssessment. Endpoints assessed for i ndirect effects include survival, growth and reproduction.

Assessment Endpoints for Desi gnated Critical Habitat

As previously discussed, designated critical habitat is assessed to evaluate actions related to the use of carbon, sawdust, potassium nitrate, sodium nitrate and su lfur cartridges that may alter PCEs of listed species’ critical habitat. Actions that may modify critical habitat are those that alter the PCEs and jeopardize the continued existen ce of the listed species. It should be noted
that evaluation of PCEs as assessment endpoints is limited to those of a biological nature ( i.e.

, the biological resource requi rements for the listed species associat ed with the critical habitat) and
those for which effects data are available.

24Adverse modification to the critical habitat of listed species includes, but is not limited to, the following, as specified by USFWS (1998):

1. Alteration of chemical characterist ics necessary for normal growth and viability of juvenile and adult endangered species.

2. Alteration or elimination of the liste d species’ food sources or prey base.

Some components of these PCEs are associ ated with physical abiotic features ( e.g. , presence and/or depth of a water body, or distance between two sites), which are not expected to be measurably altered by use of pesticides. Assessment endpoint s used for the analysis of designated critical habitat are based on the a dverse modification standa rd established by USFWS (2006).

2.8.2 Incident Reports

An ecological incident is defined as an event(s) in which pesticid e use is known or suspected of causing the death or other adverse toxicological eff ects to wild animals and plants other than the intended target species. Incidents for animals ma y include any type of fr ee-ranging wild animal, including birds, mammals, fish, reptiles, am phibians and invertebrates, although incidents involving invertebrates other than bees and crayfish are rarely reported. Plant incidents may include adverse effects to any wild plant, although almost a ll plant incident reports EFED receives are for damage to crops and ornamentals. Incidents of adverse effects to humans, pets and domestic animals are not considered ecological incidents.

There are three primary sources for obtaining in formation on ecological incidents: 1) the Ecological Incident Information System (EIIS, v. 2.1), 2) the Avian Incident Monitoring System (AIMS) and 3) 6(a)(2) incident reports. The Agency’s Ecological Incident Information System (EIIS), maintained by the Agency’s Office of Pesticide Programs, and the Avian Monitoring Information System (AIMS), maintained by the American Bird Conservancy, do not contain any reports of damage or adverse effects to non-targ et organisms attributed to the use of carbon, sawdust, potassium nitrate, sodium nitrate or sulf ur gas cartridges. There are also no reports for carbon dioxide indoor fumigant uses. No incide nts of contamination of surface, ground and drinking water have been reported to the Agency.

In addition to reviewing major incidents reco rded in EIIS and AIMS, minor incidents are recorded as aggregated incident reports in th e 6(a)(2) Incident databa se maintained by the Agency’s Office of Pesticide Programs. Pesticide registrants report certain types of incidents to the Agency as aggregate counts of incidents occurring per product per quar ter. Ecological incidents reported in aggregate re ports include those categorized as ‘minor fish and wildlife’ (WB), ‘minor plant’ (P-B), and ‘other non-target ’ (ONT) incidents. ‘Oth er non-target’ incidents include reports of adverse effects to insects and other terrestrial i nvertebrates. Alt hough there is a minor fish incident reported for sulfur, that prod uct is not a cartridge a nd is not being evaluated in the current risk assessment. For carbon, potassium nitrate, sodium nitrate and sulfur cartridges, registrants have reported 0 minor fish and wildlife incidents, 0 mi nor plant incidents, and 0 other non-target incidents.

252.9 Conceptual Model

For a pesticide to pose an ecological risk, it mu st reach ecological receptors in biologically significant concentrations. An exposure path way is the means a pesticide moves in the environment from a source to an ecological recepto r. For an ecological pathway to be complete, it must have a source, a release mechanism, an environmental transport medium, a point of exposure for ecological receptors an d a feasible route of exposure.

A conceptual model provides a written descriptio n and visual representation of the predicted relationships between the stressor (carbon, sawdust, potassium nitrate, sodi um nitrate and sulfur cartridges by-products), potential routes of exposure and the pred icted effects for the assessment endpoint. A conceptual model consists of tw o major components: a risk hypothesis and a conceptual diagram (USEPA, 1998).

2.9.1 Risk Hypotheses

A risk hypothesis describes the predicted re lationship among the st ressor, exposure and assessment endpoint response along with the rationale for their selection. Fo r this assessment, the risk is stressor-linked, where th e stressor is the rel ease of carbon, sawdust, potassium nitrate, sodium nitrate, or sulfur by-products to the en vironment. These by-pr oducts are toxic gases, product of the combustion of the cartridges material. The following ri sk hypotheses are being employed for this assessment for the by- products, not the active ingredients:

• Given the uses of carbon, sawdust, potassium nitrate, sodium nitrat e and sulfur cartridges and
their environmental fate properties, there is a likelihood of exposure to non-target terrestrial organisms to the combustion by-products.

•

When used in accordance with the label, carbon, sawdust, pota ssium nitrate, sodium nitrate and sulfur cartridges result in potential adverse effects upon the survival, growth, and reproduction of non-target terrestrial organisms.

2.9.2 Diagram

The conceptual model is a graphic representation of the risk hypothesis, and assumes that as rodenticides/ predacides with an inhalation toxic mode of action, carbon, potassium nitrate, sodium nitrate, sulfur and sawdust by-products are capable of affec ting terrestrial animals provided that environmental concen trations are sufficiently elevated as a result of proposed label uses. There is less concern for aquatic animals because exposure is expected to be minimal. Through a preliminary iterative process of examining available data, the conceptual model has been refined to reflect the likely exposure pathwa ys and the organisms that are most relevant and applicable to this assessment (Fig.2.1). It specifies the stresso rs (reaction by-products from the gas cartridge use, ( e.g. carbon monoxide, carbon dioxide, sulfur dioxide a nd nitrogen oxide), the source and/or transport pathways, exposure media, exposure point, biological receptor types and effects endpoints of potential concern.

26The stressor resulting from appli cation of gas cartridges applied to sealed burrows in open fields, rangeland, lawns, golf courses, non-crop areas or re-forested areas are ga ses, such as carbon monoxide, formed after the ignition of the cartridges. The source is the cartridge applied to the site (burrows or dens); the exposure media is i nhalation of gases that di sperse or diffuse (carbon monoxide, sulfur dioxide, and other gases that may be inhaled by te rrestrial animals that inhabit burrows, including both, vertebrates and invert ebrates), resulting in death by asphyxiation leading to reduced survival, changes in the food chain due to reduced prey, and/ or changes in habitat integrity. Modifications of PCEs are ex pected, due to reduction in prey or modification
of habitat. The label indicates that the burrows are to be sealed quickly after the cartridge is activated and inserted into the burrow, so the ga ses remain for an extended period of time inside the burrow. Exposure is expected to be minimal, except for burrowing animals.

27Fig. 2.1. Conceptual Model for Cartridge Pro ducts Containing Carbon, Sawdust, Sodium Nitrate, Potassium Nitrate and Sulfur Food chain Reduction in prey and food
Modification of PCEs related to prey availability Terrestrial
Vertebrates found
in burrows at the time of application Cartridge is applied to use site; sawdust, carbon, sodium nitrate, potassium nitrate and sulfur; combustion by-products are produced Stressor

Source

Exposure Route Application
burrow/ den

Inhalation of gas

by-products

Receptors Terrestrial
Invertebrates found in
burrows at the time of application

Attribute Change Individual organisms
Reduced survival Reduced growth Reduced reproduction Habitat integrity Reduction in primary productivity Community change
Modification of PCEs related
to habitat

282.10 Analysis Plan

In order to address the risk hypot hesis for Registration Review, the potential for direct effects to non-listed species and direct and in direct effects to listed species is estimated. In the following sections, the use, environmental fate, and eco logical effects of car bon, sawdust, potassium nitrate, sodium nitrate, and sulf ur cartridges are characterized and integrated to assess the risks. No RQs were calculated due to the waiver of fate and toxicity data. Risk will be determined by lines of evidence including method of application, mode of acti on and life history characteristics reported in the risk description section.

A refined risk assessment under the San Francisc o Bay litigation will also be conducted for the California whipsnake, the San Francisco garter snake and th e San Joaquin kit fox. Routine procedures for refined assessments for the litig ation assessment are provided in Attachment I. However, the determinations are based on lin es-of-evidence such as fate and transport characteristics and life history tr aits, with no modeling performed.

2.10.1 Measures to Evaluate the Risk Hypothesis and Conceptual Model

Measures of Exposure

There are no relevant fate or monitoring data for individual active i ngredients or mixtures, related to the gas cartridge products. No measur es of exposure based on aquatic and terrestrial models predicting estimated environmental concentrations (EECs) for carbon, sawdust, potassium nitrate, sodium nitrate and sulfur cartridges using the maxi mum-labeled application rates and methods of application are derived due to th e absence of data an d type of exposure.

However, the by-products (certain toxic gases such as carbon monoxide, car bon dioxide, sulfur dioxide and nitrogen oxide) may be transpor ted via diffusion throughout the burrows. Runoff and spray drift are not expected to be potential transport mechanisms to the aquatic and
terrestrial habitats. In this assessment, transport of cartridge by-products through diffusion (not through runoff or spray drift) is considered. Quantitative estimates of cartridge by-product exposure to non-target and endangered species, their prey and habitats are not derived (see also Section 3.2).

Measures of Effect

One-hundred percent mortality is assumed to occu r at the application site from the combustion products resulting in asphyxiation. This estimate is based on various efficacy studies and other articles in the open literature , the mode of action and the e xpected exposure of non-target organisms in burrows or dens (see Section 3.2 ). Efficacy studies support the assumption of 100% mortality, although it is conservativ e (refer to Appendix A for details).

Integration of Exposure and Effects

Risk estimation (Section 5.1) is the integration of e xposure and ecological e ffects to determine the potential ecological risk from agricultural and non-agricultur al uses of carbon, sawdust,

29potassium nitrate, sodium nitrate, and sulfur car tridges, and the likelihoo d of direct effects to non-listed species in terrestrial habitats. Fo r the assessment of car bon, sawdust, potassium nitrate, sodium nitrate, and sulf ur cartridge risks, the risk quotie nt (RQ) method is not used to compare exposure and measured toxicity values due to the waiver of data for fate and ecological effects. Other lines of evidence ( i.e. presence of combustion by- products due to application method, mode of action) are used to characterize the risk to non-listed and listed species.

The conclusion (Section 7) summarizes potential direct effects on non-listed and direct and indirect effects on listed species arising from FIFRA regulat ory actions under Registration Review regarding the use of car bon, sawdust, potassium nitrate, sodium nitrate and sulfur in fumigant gas producing cartridge products. The conclusions relative to the Alameda whipsnake, the San Francisco garter snake and the San Joa quin kit fox are also presented in section 7.

3. Exposure Assessment

Carbon, sawdust, sodium nitrate, potassium nitrate and sulfur are formulated as gas cartridges for use in active burrows or dens fo r the target pests. All the five active ingredients are naturally occurring substances whose physical properties are well understood. In addition to the cartridge use, sulfur has ag ricultural uses that ar e not assessed in this document. The purpose intended for products containing these active ingredients is to kill certain vertebrate species inhabiting burrows or dens. These cartridges are lit and placed in burrows which are rapidly sealed, to produce toxi c gases that kill the animals present at the site by asphyxiation. Pest species are not exposed to the acti ve ingredients, but to the product of their combustion. Examples of such pr oducts are carbon monoxide , nitrogen oxide and sulfur dioxide. The active ingredients are not considered as stressors , but the gas-phase byproducts are considered the stressors.

3.1 Label Application Rates and Intervals

There are six labels for carbon, sawdust, sodi um nitrate, potassium nitrate and sulfur, formulated as gas cartridges (Tab le 2.1). It is noted that saw dust and carbon products are coformulated with sodium or potassium nitrate an d, in various formulations, with sulfur. The formulated product labels legally limit the ch emicals’ potential use to only those sites and uses that are specified on the labels.

Current target pests of carbon, sawdust, sodi um nitrate, potassium nitrate and sulfur cartridges are stated in Table 2.1. Actual use in formation and usage data for carbon, sawdust, sodium nitrate, potassium nitrate and su lfur cartridges are provided in Section 2.4.3.
Five label rates reflect the percent active ingredient range of 44-54% identified in the 1993 Biological Opinion for five of the six labels. The sixth formulation, Revenge Rodent Smoke Bomb, has an active ingredient percentage of 38.8.

3.2 Terrestrial Animal Exposure Assessment

There are no EFED models currently in use to as sess the exposure of terrestrial species living in burrows, for substances such as carbon, sawdust, sodium nitrate, potassium nitrate and sulfur,

30which are formulated in cartridges. The purpose of the gas cartridge s is to treat burrows or dens with active target pests. The burrows or dens are sealed following a pplication, and the toxic gaseous by products, are anticipated to exist at high concentrations and (a) be absorbed or entrapped by the soil, where (b) they are meta bolized by soil microorgani sms or (c) enter their elemental cycles, while the remainder may be (d ) slowly lost to the environment (see Ramey et al. 1994, citing USDA 1994) and/ or diffuse/ disperse into the atmosphere afterwards. Based on the use pattern for the active ingr edients, their by-products are e xpected to be in the sealed
burrows or dens in substantial (lethal) am ounts (a conservative assumption of 100% mortality is made). A high level of acute (short term) exposure is presumed for non-listed and listed
terrestrial vertebrate and invertebrate animal s living in burrows or dens, based on the label review results (use pattern), and findings of va rious efficacy studies that show high levels of mortality for most of the organisms tested ( e.g. , refer to Savarie, et al, 1980; Matschke, et al. 1980; Fagerstone, et al. 1981; Matschke and Fagerstone, 198 4; Zhi and Chang, 1986; Matschke,

et al. 1995, and refer to Appendix A, for further deta ils about these studies). No terrestrial modeling will be conducted but exposure is pres umed for non-listed and listed organisms living in treated burrows. No potential transport from sp ray drift or run-off is expected from the use of gas producing cartridges.

For terrestrial non-listed and listed species that do not inhabit burrows or dens, no measurable exposure is expected to the cartridges toxic by -products, based on the use pattern derived from the label, used only in burrows or dens.

3.3 Terrestrial Plant Ex posure Assessment

No direct exposure to terrestrial plants is anti cipated, based on the burrow or den use pattern for
the chemicals. The TerrPlant model will not be utilized.

4. Effects Assessment

The toxicity studies for the active ingredient s used in the cartridges were waived. This assessment is limited to mixtures of carbon, sawdust, potassium nitrate, sodi um nitrate and sulfur in the cartridges. A conservative estimate of one-hundred percent mortality is assumed based on the direct effects from the combustion products. Th erefore no sub-lethal e ffects are evaluated. In addition, no ECOTOX data for individual active ingr edients will be used in the assessment. Although no ECOTOX studies were used in the a ssessment, references are provided for carbon and carbon dioxide in Appendices J- M and for inorganic nitrates in Appendices N-P. The ECOTOX rejection codes are defined in Appendix Q. In addition to the reference list, a spreadsheet noting specific toxicity tes ting details including duration, endpoints and concentrations, is presented in Appendix R for carbon and S for inorganic nitrates.

A review of the EIIS and AIMS databases for major and minor aggregate ecological incidents involving carbon, sawdust, potassi um nitrate, sodium nitrate, and sulfur cartridges was completed on November 30, 2009. There were no car tridge product terrestr ial incidents reported
in the EIIS or AIMS databases for birds. Th e EIIS database recorded no major incidents for
mammals or terrestrial invertebrates. No minor incidents were reported in the 6(a)(2) database for the gas cartridges.

315. Risk Characterization

5.1 Risk Estimation

Acute and chronic RQs are usually compared to the Agency’s levels of concern (LOCs) to identify instances where the chemical’s use with in the action area has the potential to adversely affect the non-target organisms. RQs may also be used to eval uate the potential impact on listed species via direct toxicity or indirectly based on direct effect s to their food supply and their designated critical habitat.

A conservative estimate of one-hundred percent mortal ity at the application s ite is expected from asphyxiation due to the combusti on products. This assumption is realistic based on the use pattern, the mode of action, and various effi cacy studies (refer to Appendix A for a brief summary of such studies).

5.2 Risk Description

5.2.1 Lines-of-evidence

No modeling was conducted and no incidents were reported for the cartridges. The impact of using the cartridges was based on the pesticide’s method of applic ation and mode of action. In addition, ecological characteristics of non-liste d and listed species were combined with information from the USFWS memos, a Biologi cal Opinion (1993) and a 1996 letter concurring with EPA Region IX’s NLAA determination for the SFGS and SJKF (Attachment IV).

USFWS Memos

There were four memos discussing the effects of the cartridges on listed species and one Biological Opinion (1993). One memo (010, 1981) addressed the gas fumigant magnesium phosphide, but was later extended to registered gas fumigants under memo (023, 1982). The request covered six listed sp ecies: black-footed ferret ( Mustela nigripes ), Eastern indigo snake ( Drymarchon corais couperi ), San Joaquin kit fox ( Vulpes macrotis mutica ), Utah prairie dog ( Cynomys parvidens ), blunt-nosed leopard lizard ( Gambelia Crotaphytus silus ) and the desert tortoise ( Gopherus agassizil ) and its critical habitat The opinion concludes that these species will be adversely affected by the use of these products and the only means of mitigating jeopardy
is to restrict use in areas where the species are found.

Another memo (016, 1981) required changes for the endangered species language on the label for sodium nitrate gas cartridges. Accordingly, the new label restricts use in areas where red wolves, gray wolves, and the San Joaquin kit fox may have dens.

Memo (023, 1982) responded to a request for info rmal consultation for a label review of gas cartridges used in burrow fumigation and the impact on the black-footed ferret ( Mustela nigripes ), Eastern indigo snake ( Drymarchon corais couperi ), San Joaquin kit fox ( Vulpes

macrotis mutica ), Utah prairie dog ( Cynomys parvidens ), blunt-nosed leopard lizard ( Gambelia

32Crotaphytus silus ) and the desert tortoise ( Gopherus agassizil ) and its critical habitat. The memo
indicates that inclusion of enda ngered species language from pr eviously approved gas cartridges for those species will avoid jeopardy.

The fourth memo 036 (1984) responded to a request for review of previous biological opinions on prairie dog toxicants including gas cartridges. To preclude jeopardy for the black-footed ferret, a pre-control survey must be conducted in accordance with approv ed USFWS methods. If no signs of ferret presence are f ound, the pesticide may be used. If signs of ferret presence are found, consultation is required for case-by-case op inions. This requirement must be included on all prairie dog toxicant labels.

Biological Opinion

The 1993 Biological Opinion covered seventee n listed species: bl ack-footed ferret ( Mustela nigripes ), Eastern indigo snake ( Drymarchon corais couperi ), San Francisco garter snake ( Thamnophis sirtalis tetrataenia ), San Joaquin kit fox ( Vulpes macrotis mutica ), Utah prairie dog ( Cynomys parvidens ), Hualapai Mexican vole ( Microtus mexicanus hualpaiensis ), Point Arena mountain beaver ( Aplodontia rufa nigra ), Fresno kangaroo rat ( Dipodomys nitratoides exilis ), giant kangaroo rat ( Dipodomys ingens ), Stephens kangaroo rat ( Dipodomys stephensi ), tipton kangaroo rat ( Dipodomys nitratoides nitratoides ), Morro Bay kangaroo rat ( Dipodomys

heermanni morroensis ), blunt-nosed leopard lizard ( Gambelia Crotaphytus silus ), Coachella Valley fringe-toed lizard ( Uma inomata ), island night lizard ( Xantusia riversiana ), Gopher Tortoise ( Gopherus polyphemus ), and the desert tortoise ( Gopherus agassizil ) and its critical habitat. Jeopardy calls for mammals were made fo r the Black-footed ferret, the Fresno kangaroo rat, Hualapai Mexican vole, Giant kangaroo ra t, Morro Bay kangaroo ra t, Stephen’s kangaroo rat, Tipton kangaroo rat, Point Arena Mountai n beaver and the San Joaquin kit fox. A no jeopardy call was made for the Utah prairie dog. Je opardy calls for reptiles were made for the blunt-nosed leopard lizard, Easter n indigo snake, the gopher tortoise and the San Francisco garter snake. A no jeopardy call was made for the Co achella Valley fringe-t oed lizard, the desert tortoise and the Island night lizard.

For species identified with jeopardy calls, alternativ es are proposed to reduce or avoid jeopardy.
No incidental take is allowed for the Black-foot ed ferret. Ferret surveys by trained staff are requested based on colony size. A proposal fo r EPA to maintain records on amount of acres
controlled or the amount of chemical sold is included in the BO.

The alternatives for the San Joaquin kit fox, Po int Arena mountain beav er, Fresno kangaroo rat, the giant kangaroo rat and the Tipton kangaroo rat include limiting use to qualified individuals within the occupied habitat. An unquantifiable level of incidental take may occur even with the implementation of the alternatives. Therefore to minimize anticipated take, EPA must establish a monitoring enforcement program. The alternatives for the blunt-nosed leopard lizard and the San Francisco garter snake also limit the use of th e cartridges to trained staff and request the monitoring program but also incl ude restrictions on use during th e lizard inactivity period unless approved by the USFWS.

33The alternatives for the Stephen’s kangaroo rat include either allowing no use in the occupied habitat or only allowing trained staff to use the cart ridges in occupied habita t. No incidental take is anticipated or authorized following implementation of the alternatives.

The alternatives for the Hualapai Mexican vole, the Morro Bay kangaroo rat, the Gopher tortoise, the Eastern indigo snake include no use in the occupied territory. With implementation of the alternative measures, no in cidental take is allowed. The Gopher tortoise also allows no incidental take with the impleme ntation of no use in the occupied habitat, but lists geographical restrictions for the habitat description.

The California Department of Pesticide Regulati on (Cal DPR) is established as a non-federal representative for purposes of conducting consulta tion with the US Fish and Wildlife Service, up to and including informal consultation. Info rmal consultation may be conducted where a determination is made by the action agency (or th eir non-federal representative) that an action is “Not Likely to Adversely Affect” a listed speci es. At the request of Cal DPR, EPA Region 9 requested the US Fish and Wildlife Service revi ew bulletins put in place by Cal DPR, for the protection of listed species and to concur that those bulletins were adequate replacements for the
RPA’s indicated in the 1993 BO relative to cer tain species, including the SFGS and SJKF, and burrow fumigants. On November 1, 1996 the US Fi sh and Wildlife Service responded indicating that the Cal DPR bulletins were in fact, adequa te and could substitute for the RPAs in the 1993 BO relative to the species and bu rrow fumigants covered in that BO . The letter further indicated that species not covered in the BO or the effect of pesticides not covered in the BO, such as the CAW, would require further consultation.

Life Histories for the California Alameda Wh ipsnake (CAW), the San Francisco Garter Snake (SFGS) and the San Joaquin Kit Fox (SJKF)

The CAW, SFGS and SJKF are addressed in the Registration Review and the SFB litigation. In addition to the USFWS memos and the Biological Opinion, life history information will be used to support the determinations. The cartridges are used on target small mammals that live in burrows or dens, therefore the life histories for the CAW, SFGS and SJ KF were reviewed to
determine use of burrows or de ns for shelter or reproduction.

There is a report noting the use of burrows as shelter for the CAW, which would indicate potential effects from the use of the gas cartridge s. The most common types of shelter reported in grassland and scrub communities were small rode nt burrows and rock crevices (USFWS, 2002; Appendix T). The CAW is the only species under the San Francisco Bay litigation designated as having critical habitat (Appendi x U). The habitat was designated for the CAW on October 2, 2006 (USFWS, 2005 and 2006) using the PCE’s summarized in Appendix V.

The life history for the SFGS reports the use of mammal burrows which would indicate potential
effects from the use of the car tridges (Appendix W). SFGSs may be found in densely vegetated ponds near open hillsides, which allow them to sun themselves, feed, and find shelter in rodent burrows (USFWS, 1985; USFWS, 2007; Nature Serve, 2007). SFGSs may also hunt prey (amphibians) in rodent burrows during the summer (Goals Project, 2000).

34The life history characteristics for the SJKF i ndicate the use of burrows indicating a potential impact from cartridge use (Appendix X). SJKF s may use dens for shelter from adverse environmental conditions, reproduction, and esca pe from predators (USFWS, 1998 and 2008). Although kit foxes may dig their own dens, they may also modify and use those already constructed by other animals (ground squirrels, badgers, and coyotes), or use human-made structures (culverts, abandoned pipelines, or banks in sumps or roadbeds) (USFWS, 1998 and 2008).

3536 Table 5.1. Summary of Current Distribut ion, Habitat Requirements, and Life History Information for the Assess e Listed Species 1

Assessed Species Size Current Range Habitat Type Designated
Critical
Habitat? Reproductive Cycle Diet

San Francisco
Garter Snake (SFGS) ( Thamnophis

sirtalis

tetrataenia ) Adult (46-131 cm in length), Females – 227 g,
Males – 113 g; Juveniles – 2 g (Cover Jr. and Boyer, 1988) (18–20 cm in length) San Mateo County Densely vegetated freshwater ponds

near open grassy hillsides; emergent vegetation; rodent
burrows No Oviparous Reproduction 2 Breeding : Spring (Mar. and Apr.) and Fall (Sept. to Nov.)
Ovulation and Pregnancy : Late spring and early summer Young : Born 3-4 months after mating Juveniles : fro g (Pacific tree f r CRLF, and bu l depending on s and insects
Adults : prim a frogs (mainly CRLFs; also
b ullfrogs, toa d
lesser extent n e freshwater fis h invertebrates; i
and small ma m San Joaquin
Kit Fox (SJKF) ( Vulpes

macrotis

mutica ) Adult ~2 kg Alameda,

Contra Costa, Fresno, Kern, Kings, Madera, Merced, Monterey,

San Benito,

San Joaquin,
San Luis Obispo,

Santa Barbara,

Santa Clara, Stanislaus,
Tulare and

Ventura
counties A variety of habitats, including grasslands, scrublands ( e.g ., chenopod scrub and sub-shrub scrub), vernal pool areas, oak woodland, alkali meadows and playas, and an agricultural matrix of row crops, irrigated pastures, orchards, vineyards, and grazed annual grasslands. Kit foxes dig their own dens, modify and use those already constructed by other animals (ground squirrels, badgers, and coyotes), or use
human-made structures (culverts, abandoned pipelines, or banks in sumps or roadbeds). They
move to new dens
within their home range often (likely to avoid predation by coyotes) No, but has designated

core areas Mating and conception : late December - March. Gestation period : 48 to 52 days.
Litters born : February -
late March

Pups emerge from their
dens at about 1-month of age and may begin to disperse after 4 – 5 months usually in Aug. or Sept. Small animals including blac k hares, desert cottontails, mi c kangaroo rats, squirrels, bird s lizards, insect s grass. It satisf i
moisture requirements f

p rey and does depend on fre s

sources.

CA Alameda Whipsnake (CAW) ( Masticophis

lateralis euryxanthus ) 3 – 5 ft Contra
Costa and
Alameda
Counties

in
California (additiona

l

occurrenc es in San Joaquin
and Santa
Clara Counties) Primarily, scrub and chaparral
communities. Also found in grassland, oak savanna, oak-bay woodland, and riparian areas. Lands containing rock outcrops, talus, and
small mammal
burrows. Yes Emerge from hibernation and begin mating from late March through mid-June. Females lay eggs in May through July. Eggs hatch from August through
November. Hibernate during the winter
months. Lizards, small mammals, ne s b irds, other sn a including rattl e5.2.2 Risk Conclusions

The risk description synthesizes an overall conclusion regarding th e likelihood of adverse impacts leading to direct effect s for non-listed species and direct or indirect dietary effects determination ( i.e ., “no effect,” “may affect”) for listed species from the use of cartridges from outdoor terrestrial exposures. The agency determined that there was the potential for adverse direct effects from the application of the cart ridges from the combus tion products to non-listed birds, mammals and terrestrial invertebrates i nhabiting burrows or dens . There is also the potential for adverse direct e ffects to non-listed reptiles and amphibians inhabiting burrows or dens because birds are used as surrogates for those species. The determination is based on asphyxiation from the combustion products formed af ter the cartridge is ignited in the burrow or
den and the burrow or den is sealed to retain the gases at the site.

An assessment is also conducted for effects on list ed species. If there is a determination that there is a potential for direct or indirect effects on listed species, a “may affect” determination is made. Following a “may affect” determination for listed species and critical habitat, additional information is considered to refine the potential for exposure and effects, and the best available information is used to distinguish those actions that “may affect, but ar e not likely to adversely affect” (NLAA) from those actions that are “likely to adversely affect” (LAA) endangered species and its critical habitat.

The criteria used to make determinations that the effects of an acti on are “Not Likely to Adversely Affect” the listed species and its design ated critical habitat include the following:

• Significance of Effect : Insignificant effects are those that cannot be meaningfully measured, detected, or evaluated in the contex t of a level of effect where “take” occurs for even a single individual. “Take” in this context means to harass or harm, defined as the following:

 Harm includes significant habitat modificat ion or degradation that results in death or injury to listed species by significantly impairing behavioral patterns such as breeding, feeding, or sheltering.

 Harass is defined as actions that create the likelihood of injury to listed species to such an extent as to significantly disrupt normal behavior patterns which include, but are not limited to, br eeding, feeding, or sheltering.

• Likelihood of the Effect Occurring : Discountable effects are those that are extremely unlikely to occur.

• Adverse Nature of Effect : Effects that are wholly benefi cial without any adverse effects
are not considered adverse.

Although there is no fate or toxicity data ava ilable for modeling and no reported major incidents the Agency makes a “May Affect, LAA” determ ination for listed burrowing species (birds, mammals, insects, and reptiles and amphibians using birds as a surrogate) for survival as an
acute direct effect based on as phyxiation from the combustion products. The effect from the application of the cartridges is localized to the a pplication site based on th e label instructions to seal the burrow or den following the applicati on. Supporting evidence is based on habitat and diet life history information (Nat ure Serve, 2009) for taxa represen ting listed species identified in

37Appendix B. Additional supporting information is provided from a 1993 Bi ological Opinion as well as memos from the USFWS indicating potentia l risk to terrestrial mammals and reptiles without specific mitigation for each species id entified. The BO iden tified mitigation for 17 specific species. This information was include d on two labels, the Gas Cartridge and the Large Gas Cartridge. Six of those identified listed spec ies were also included on three labels (Dexol Gopher Gasser, Revenge Smoke Bomb and SMOKE’e m). One label does not include specific listed species information (Giant Destroyer).

Potential indirect effects of survival, growth and reproduction on reduction in prey for listed species also resulted in a “May Affect, LAA” for birds, mammals, reptiles and amphibians based on asphyxiation from the combustion products. The indirect effects from cartridge application are not limited to species inhabiting burrows or dens because some prey are included in the diets of listed species that do not i nhabit burrows or dens. Supporting evidence is based on diet life history information for taxa repr esenting listed species consuming prey with burrow/den habitats as reported by USFWS which ar e identified in Appendix C.

Indirect effects also include potential habita t modification. Habitat modification is based on reduction in prey as well as ch anges in habitat used for shelte r or reproduction. There is a
“Habitat Modification” determination for listed birds, mammals, reptiles and amphibians based on reduction in prey based on a conservative estimate of 100% mortality from the combustion products as well as reduction in sh elter. Shelter can be reduced due to sealing the burrow or den entrances following application of the cartridges, especially for species that use other animal
burrows or dens rather than creating their own burrows or de ns. Habitat Modification for terrestrial invertebrates is based on limiting access to the burrows or dens after the pesticide is applied through sealing entrances. The Habitat Modification for plan ts is based on potential for reduction in seed dispersal. Because mammals may transport seeds in their fur, dispersal may be
reduced due to the number of mammals availabl e in a geographic area. Supporting evidence is based on habitat life history information for taxa representing listed species consuming prey with burrow/den habitats as reported by USFW S which are identified in Appendix D.

EPA previously requested the registrant to modify labels for the Gas Cartridge and the Large Gas Cartridge based on conclusions from the Biol ogical Opinion (1993). The Biological Opinion identified 17 listed species with specific mitigat ion for each such as time of use and geographic boundaries. In addition, memos from USFWS indicated risk to identified mammals and reptiles and included mitigation specific to six identi fied species. Based on those memos, six listed species were included on labels for Dexol Gopher Gasser, SMOKE’em, and Revenge Smoke Bomb. Those modified labels provide the basis for the current assessment. Additionally, Cal DPR’s bulletins were deemed adequate replacements for RPAs listed in the 1993 BO for certain species in CA. Therefore, the species for wh ich labeling was changed relative to the 1993 BO and those covered by the Cal DPR bulletins wh ich also were addressed in the 1993 BO, including the San Francisco garter snake and San Joaquin kit fox, ar e adequately protected at this time from potential effects of the burrow fumiga nts being assessed here. Nonetheless, during
consultation with the US Fish and Wildlife Se rvice on other species po tentially affected, EPA will confirm that the measures in place remain ade quate and that the ranges of these species have
remained constant since the 1993 BO a nd the 1996 letter to EPA Region 9.

38Consultation will be reinitiated w ith the U. S. Fish and Wildlife Service under Section 7 of the Endangered Species Act. A screening list of endangered species with the potential to be adversely impacted by potassium n itrate, sodium nitrate, carbon, sawdust and sulfur cartridges, including the California whipsnake, is provided in Appendices B, C and D. For the SFGS and the SJKF the use of cartridges is determined to “Not Likely to Adversely Affect (NLAA)”. The
NLAA determination is based on the 1996 USFW S response to allow the use of Cal DPR bulletins as a replacement for RPA’s noted in the 1993 BO. The use of the subject pesticides is determined to have No Effect for all other sp ecies not included in Appendices B, C and D, and
critical habitat.

5.2.2 Assessment Endpoints for Endocrine Disruptor

As required under FFDCA section 408(p), EP A has developed the Endocrine Disruptor Screening Program (EDSP) to determine whether certain substances (inc luding pesticide active and other ingredients) may have an effect in humans or wildlife si milar to an effect produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator may designate.” The EDSP employs a two-tiered ap proach to making the statutorily required
determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a chemical substance to interact with the estrog en, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go th rough Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal systems will proceed to the next stag e of the EDSP where EPA will determine which, if any, of th e Tier 2 tests are necessary base d on the available data. Tier 2 testing is designed to identify a ny adverse endocrine related eff ects caused by the substance, and establish a dose-response relationship between the dose and the E, A, or T effect.

Between October 2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, which contains 58 pesticid e active ingredients and 9 inert ingredients.
This list of chemicals was selected based on th e potential for human exposure through pathways such as food and water, residen tial activity, and certain post-applic ation agricultural scenarios.
This list should not be construed as a lis t of known or likely endocrine disruptors.

Carbon, sawdust, sodium and potassium nitrat es, and sulfur are not among the group of 58 pesticide active ingredients on the initial list to be screened under the EDSP. Under FFDCA sec. 408(p) the Agency must screen all pesticide ch emicals. Accordingly, EPA anticipates issuing
future EDSP test orders/data call-ins for all pesticide active ingredients.

For further information on the status of the ED SP, the policies and procedures, the list of 67 chemicals, the test guidelines and the Tier 1 screening battery, pleas e visit our website: http://www.epa.gov/endo/

.

5.3 Action Area Spatial Analysis

In the case of a nationwide risk assessment conducted for Registration Review, the action area will encompass the entire U.S. and its territories. The purpose of defining the action area as the
entire U.S. and its territories is to ensure that the initial area of cons ideration encompasses all areas where the pesticide may be used now and in the future, including the potential for off-site

39transport via spray drift and downstream dilu tion. Additionally, the concept of a nationwide
action area takes into account th e potential for direct and indi rect effects and any potential
modification to critical habitat ba sed on ecological effect measures associated with reduction in survival, growth, and reproduction, as well as the full suite of sub-le thal effects available in the
effects literature.

It is important to note that the nationwide action area does not imply that di rect and/or indirect
effects and critical habitat modifi cation are expected to or are likely to occur over the full extent of the action area, but rather to identify all listed species and critical habi tat that may potentially be affected by the action. The Agency will use mo re rigorous analysis including consideration of available land cover data, toxi city data, and exposure information to determine areas where individual listed species and de signated critical habitat may be affected or modified via endpoints associated with reduced survival, growth, or reproduction.

The initial action area for the refined litigati on assessment for the CAW, SFGS and the SJKF
includes the entire state of California. Howeve r, due to the NLAA determination for the SFGS and the SJKF, The spatial analysis accounts for pot ential direct and indir ect effects for the CAW
based on the LAA determination from the use of the cartridges. A spatial an alysis is provided in Appendix Y.

6. Uncertainties

6.1 Exposure Assessment Uncertainties

The screening-level risk assessment usually focu ses on characterizing potential ecological risks resulting from a maximum use scenario, which is determined from labeled statements of maximum application rate and numbe r of applications with the s hortest time interval between applications. The frequency at which actual uses approach this maximum use scenario may be dependant on pest resistance, timi ng of applications, cultural practi ces, and market forces. It is
noted that several of these items do not apply to cartridge products ( e.g. application rate). Instead, cartridges are lit and applied to a num ber of cavities of the active burrows or dens, which are sealed. The intensity of the impact of the use of cartridge products may depend on the
distribution of these car tridges in the field.

During the problem formulation stage of the regist ration review, all the environmental fate data for the uses of gas cartridges were waived. This decision was based on the limited exposure expected to the active ingredients. At this ti me, there are no data on the environmental fate of the by-products. Not all the by-products have been identified. A degree of uncertainty exists on
the lack of environmental fate data for these compounds; however, some information was inferred from the open lite rature, about the fate of the reaction by-products.

Another factor affecting the le vel of exposure is the length an d complexity of the treated burrows. This includes the burrow configuration, size and shape (see Matschke, Fagerstone & Elias 1980). If the burrow system is completely closed, the dead air may delay diffusion of the gases, and the toxicant may be lost through ab sorption by the soil lining the tunnel (see Matschke

40et al. 1995; please, note that the auth ors make a point that the soil li ning is also moist, but see the next uncertainty).

The soil moisture and texture have been identified as important factors a ffecting the survival of tested species in efficacy studies. Diffusion of the toxic gases may increase in dryer or porous soils, increasing the su rvival (Matschke & Fagerstone, 1984, see also label for Dexol Gopher Gasser, Reg. No. 192-49). The gases generated by the cartridges combustion disperse into the atmosphere or are absorbed in the soils, where they may undergo metabolization by soil microorganisms (Ramey et al., 1994, citing USDA, 1994).

The length of the cartridge’s fuse may be a fact or affecting non-target species survival, since a longer fuse would allow more time to seal the burrow (see Matschcke et al., 1980 and Fagerstone et al., 1981).

The “size” of the cartridge may be a factor affect ing the survival of non-ta rget species present in the burrows. One study (Fagerstone et al., 1981) recommended the use of larger size cartridges (increasing the mass of the total active ingredients, but main taining the same proportion), to improve their efficacy. In a follow up study (Matsc hke & Fagerstone, 1984) they tested the same species (Richardson’s ground squirrel, Spermophilus richardsonii ) with a larger sized cartridge, with improved efficacy results.

There is also uncertainty in the use of the cartridg es. It appears that the acreage treated with gas cartridges is usually relatively small, as suggested by an informational sheet from the Montana Department of Agriculture. Accord ing to the leaflet, available in the Internet, fumigants, such as cartridge products, “are effective tools for follow up of poison bait applications.” It further says that, “Burrow fumigants can also be used as a primary control technique although cost of materials and labor generally re strict their use to small acreag es or sparse populations.” Hygnstrom & VerCauteren (2000) ev aluated the effectiveness and co st of five burrow fumigants used to manage black-tailed prairie dogs: me thyl bromide, chloropicrin, methyl bromidechloropicrin mixture, aluminum phosphide and ga s cartridges. (At the present time, methyl bromide and chloropicrin are not registered for th is use.). No difference in efficacy was found among treatment methods ( ≥ 95% reduction); but costs of alum inum phosphide and gas cartridges were around twice that for the other fumigants.

Limitations for county level usage data obtaine d from California’s Depa rtment of Pesticide Regulation Pesticide use Report (CDPR) incl ude only years that re ported a methodology for removing outliers in terms of area treated and pounds applied. CDPR PUR documentation indicates that errors in the data may include the following: a misplaced decimal; incorrect measures, area treated, or units; and reports of dilu ted pesticide concentrati ons. In addition, it is possible that the data may contain reports for pe sticide uses that have been cancelled. The
CPDR PUR data does not include ho me-owner applied pesticides; th erefore, residential uses are not likely to be reported (note that the cartridges should not be used in residential settings). As with all pesticide usage data, th ere may be instances of misuse and misreporting. The Agency
made use of the most current information and in cases where there were discrepancies; the most
conservative information was used.

41Publicly available data from the California De partment of Pesticide Regulation was used to outline the pounds of carbon used for cartridges in California over the three most recent years available at the time the data was gathered (2003-2005). Uses repor ted in the CDPR PUR database include applications to parks, golf c ourses, cemeteries, range land, pastures, and along roadside and railroad rights-of-way.

Publicly available data from the California De partment of Pesticide Regulation was used to produce Table 2.3, outlining the pounds of sawdust us ed in California over the three most recent years. Only 0.143 to 1.417 lbs of sawdust were us ed from 2003 to 2005 in California, and they were mostly used for landscape ma intenance and vertebrate control.

For sulfur containing cartridges, the California Department of Pesticide Regulation (CDPR) use
information data indicate that the use for “v ertebrate control” in the period of 2003 to 2005 ranged from 453 to 4418 lb. Sulfur has uses other than cartridges; therefor e, the usage table is
not included.

6.2 Effects Assessment Uncertainties

Efforts are made to select the organisms most likely to be affected by the type of compound and usage pattern; however, there is an inherent uncertainty in extrap olating across phyla.

A conservative assumption of 100% mortality is a ssumed for any animal at the application site due to the combustion products a ssociated with the use of carbon, sawdust, potassium nitrate, sodium nitrate and sulfur cartridges. This assumption is supported by various efficacy studies (refer to Appendix A). However, for certain species, it was f ound that the efficacy was lower ( e.g. for badgers). For some species, there is the pot ential for an animal to avoid the effects of the cartridges based on behavi oral cues. Some species ( e.g. wood chucks and badgers) emerge from burrows when they are aware of a ny action to seal one of the entrances. The species habits may affect their survival. In Ramey (1995), a st udy performed with badgers, it was speculated that the test species could pl ug the burrow and dig away by backfilling the tunnel behind them; therefore, avoiding the gases.

The mortality or survival of ta rget and non-target species presen t in burrows at the time of treatment may depend on the body wei ght of the species (Matschcke et al., 1980 and Fagerstone et al., 1981).

No secondary toxicity from consumption of de ad animals is expected for carbon monoxide cartridges, based on a study by Savarie et al., 19 80; however, secondary toxicity for other gas cartridges is uncertain.

7. Summary and Conclusions

42Ramey & Schafer (1996), described concisely th e sodium nitrate plus carbon cartridge, as follows: “The gas cartridge is a pyrotechnic device and is composed of two parts: 1) the tube – a cardboard cylinder closed by cardb oard caps at both ends contai ning the formulated product, predominantly sodium nitrate and charcoal; and 2) the fuse – a fireworks fuse inserted through one end cap into the combustible mixture and causes it to ignite. When the burning gas cartridge is used in a confined space w ith a limited air supply, such as a burrow or den, it can produce
lethal concentrations of carbon mo noxide.” This description is illustrative also of cartridges containing other active ingredients.

The cartridges are designed to be ignited and burn, releasing toxic gases, such as carbon monoxide and sulfur dioxide, and other soli d compounds. The active ingredients, carbon, sawdust, sodium nitrate, potassium nitrate and su lfur, are not the stressors. The stressors are the gases released after the combustion reaction. The inhalation of such toxic gases is the cause for asphyxiation of the target organism; therefore, the effect most likely to be observed, which occurs on a short time basis, is mortality. No substantial chronic or subchronic effects are expected. The effects of gas cartridge products should be confined within burrows or dens, and not outside of them. Eventually, the gases are dispersed in the environm ent or absorbed by the soil, where they are not expected to harm w ildlife or the environmen t, while the solids byproducts remain in the burrows. One exampl e of such a solid is sodium carbonate (Na 2 CO 3 ), which is nearly inert and appears to be of low toxicity (rats LD 50 of 4090 mg/kg, as per its MSDS). It is of no ecological effects concern.

The gas cartridges are applied to active burrows in open fields, rangeland, lawns, golf courses, non-crop areas or re-forested areas, or dens in rangeland, crop and non-cr op areas. The exposure media/source is gas diffusion (c arbon monoxide, sulfur dioxide and/ or other gases that may be inhaled by terrestrial animals that inhabit burrows or dens), re sulting in death by asphyxiation leading to reduced survival as th e assessment endpoint for direct eff ects. The label indicates that the burrows or dens are to be sealed quickly afte r the cartridge is ignited and inserted into the burrow or den, so the gases remain at toxic (letha l) levels for a period of time inside the burrow
or den. There are instructions de scribing soil conditions for optimum benefits from the cartridges
used in burrows as well as instruc tions on sealing burrows and dens.

An initial review is conducted to determine the potential effect on non-listed species from the use of cartridges from outdoor terrestrial exposures . The Agency determined that there was the potential for adverse direct effects from the a pplication of the cartri dges from the combustion products to non-listed birds, mammals and terrestr ial invertebrates inhabi ting burrows or dens. There is also the potential for adverse direct effects to non- listed reptiles and amphibians inhabiting burrows or dens because birds are used as surrogates for those species. There is no direct effect expected for terr estrial plants. The determinations are based on asphyxiation from the combustion products formed after the cartridge is ignited in the burrow or den and the burrow
or den is sealed to reta in the gases at the site.

In fulfilling its obligations under Section 7(a)(2) of the Endangere d Species Act, the information presented in this listed species risk assessment represents the best data currently available to assess the potential risks of car bon, sawdust, potassium nitrate, sodium nitrate and sulfur cartridge combustion products to listed species. If there is a determination that there is a

43potential for direct or indirect effects on listed species, a “m ay affect” determination is made. Following a “may affect” determination for liste d species and critical habitat, additional information is considered to refine the potential for exposure and effects, and the best available information is used to distinguish those actions that “may affect, but ar e not likely to adversely affect” (NLAA) from those actions that are “likely to adversely affect” (LAA) endangered species and its critical habitat.

The Agency makes a “May Affect, LAA” determ ination for listed burrowing species (birds, mammals, insects, and reptiles and amphibians using birds as a surrogate) for survival as an
acute direct effect based on as phyxiation from the combustion products. The effect from the application of the cartridges is localized to the a pplication site based on th e label instructions to seal the burrow or den following the applicati on. Supporting evidence is based on habitat and diet life history information for taxa representing listed specie s identified in Appendices B.

Additional supporting information is provided from a 1993 Biologica l Opinion as well as memos from the USFWS indicating jeopardy to terrest rial mammals and reptiles with specific alternatives for each species identified. The BO identified alternatives for 17 specific species. This information was included on two labels, th e Gas Cartridge and the Large Gas Cartridge. Six of those identified listed species were al so included on three labels (Dexol Gopher Gasser, Revenge Smoke Bomb and SMOKE’em). One labe l does not include specific listed species information (Giant Destroyer).

The BO also indicated that even with implementa tion of the alternatives, there was still risk for the San Joaquin kit fox, Point Ar ena mountain beaver, Fresno kanga roo rat, giant kangaroo rat, and Tipton kangaroo rat resulting in an unquantifia ble level of incidental take. Although, the
current labels reflect the need to limit use in the habitat of the Black-footed ferret, San Joaquin kit fox, Utah prairie dog, blunt-nos ed leopard lizard, Eastern indigo snake and desert tortoise, the Agency will confirm these measures remain prot ective and that habitat range has not changed.

Potential indirect effects of survival, growth and reproduction on reduction in prey for listed species also resulted in a “May Affect, LAA” for birds, mammals, reptiles and amphibians based on asphyxiation from the combustion products. The indirect effects from cartridge application are not limited to species inhabiting burrows or dens because some prey are included in the diets of listed species that do not i nhabit burrows or dens. Supporting evidence is based on diet life history information for taxa repr esenting listed species consuming prey with burrow/den habitats as reported by USFWS which ar e identified in Appendix C.

Indirect effects also include potential habita t modification. Habitat modification is based on reduction in prey as well as ch anges in habitat used for shelte r or reproduction. There is a
“Habitat Modification” determination for listed birds, mammals, reptiles and amphibians based on reduction in prey based on a conservative estimate of 100% mortality from the combustion products as well as reduction in sh elter. Shelter can be reduced due to sealing the burrow or den entrances following application of the cartridges, especially for species that use other animal
burrows or dens rather than creating their own burrows or de ns. Habitat Modification for terrestrial invertebrates is based on limiting access to the burrows or dens after the pesticide is applied through sealing entrances. The Habitat Modification for plan ts is based on potential for

44reduction in seed dispersal. Because mammals may transport seeds in their fur, dispersal may be
reduced due to the number of mammals availabl e in a geographic area. Supporting evidence is based on habitat life history information for taxa representing listed species consuming prey with burrow/den habitats as reported by USFW S which are identified in Appendix D.

These determinations are based on lines of evid ence using the best avai lable information. The
determinations are summarized in Tables 7.1 for th e initial screen and 7.2 fo r the listed species. The determinations for the three species for whic h refinements have been made are presented in
Table 7.3 and Table 7.4.

Table 7.1. Potential Direct Effects on Non- Listed Species Inhabiting Burrows and Dens for the Use of Carbon, Sawdust, Pota ssium Nitrate, Sodium Nitrate and Sulfur Cartridges

Species Assessment Endpoint Description of Results of Risk Estimation

Burrowing Birds

Burrowing
Mammals

Burrowing Reptiles

Burrowing Amphibians

Burrowing

Terrestrial

Invertebrates Survival There is a potential for acute dir ect adverse effects on burrowing species based on asphyxiation from the combustion products at the site of application.

7.2 Effects on Listed Species for the Use of Carbon, Sawdust, Potassium Nitrate, Sodium Nitrate and Sulfur Cartridges

45Species Assessment Endpoint Effects

Determination Description of Results of Risk Estimation

Direct Effects

Terrestrial (Juveniles and adults)

Burrowing
Birds

Burrowing
Mammals

Burrowing Reptiles

Burrowing Amphibians

Burrowing
Terrestrial
Invertebrates Direct Effects
Survival of
individuals
via direct
effects on
terrestrial organisms May Affect

LAA The determination for acute direct effects is based on 100% mortality from asphyxiation based on the combustion products following application.

Indirect Effects

Birds

Mammals

Reptiles

Amphibians Survival of
individuals
via reduction of prey ( i.e., birds,
terrestrial mammals, reptiles,
terrestrial phase amphibians
and terrestrial invertebrates) May Affect

LAA The determination for acute indirect effects is due to an inability to measure the effect for reduction in prey based on asphyxiation from the combustion products. The reduction inprey may affect both burrowing and nonburrowing listed species consuming animals

with burrow/den habitats.

Birds

Survival of endangered Habitat Modification There is a “Habitat Modification” based on a reduction in prey from asphyxiation for both burrowing and non-burrowing species.

467.2 Effects on Listed Species for the Use of Carbon, Sawdust, Potassium Nitrate, Sodium Nitrate and Sulfur Cartridges

Species Assessment Effects Endpoint Determination Description of Results of Risk Estimation

Mammals

Reptiles

Amphibians

Terrestrial

Invertebrates There is a “Habitat Modification” determination for burrowing species based on a reduction in cover/shelter. Use of the pesticide

results in reduced access to burrows for shelter or reproduction.

Terrestrial

Plants species via

effects on habitat ( i.e.,

reduction in prey, shelter, riparian vegetation)

There is a habitat modification determination for terrestrial plants based on the potential for reduction in seed dispersal.

47Table 7.3 Effects Determination Summary for Effects of Potassium and Sodium Nitrate Cartridges for Three Listed Species
Species Effects
Determination Basis for Determination

Potential for Direct Effects Terrestrial-phase (Juveniles and Adults) :

Habitats for the snake include shrub communities and adjacent habitats of grassland, savanna and oak-bay woodland. The most common types of retreat site in both the grassland and scrub communities are small rodent burrows and rock crevices, with brush piles, deep soil crevices and debris piles also used
for cover/shelter. The determina tion for acute direct effects is based on 100% mortality from asphyxiation based on the combustion products following application if applied to a burrow in which the snake is residing during application.

Potential for Indirect Effects Alameda Whipsnake ( Masticophis

lateralis euryxanthus ) (CAW) May Affect, Likely to Adversely Affect (LAA)

Terrestrial prey items, riparian habitat

There is an “LAA” determination for acute indirect effects due to prey reduction for the CAW consuming lizards, snakes and small mammals that may inhabit burrows. The prey may be present at the site of applicatio n, which results in mortality for the prey.

Potential for Direct Effects Terrestrial-phase (Juveniles and Adults) :

The SFGS uses densely vegetated ponds near open hillsides where they can sun themselves, fe ed, and find shelter in rodent burrows. Rodents are targets for nitrate cartridges. The determination for potential acute direct effects is based on 100% mortality from asphyxiation based on the combustion products following application if applied to a burrow in which the snake is residing during application. US FWS has indicated measures put in place by Cal DP R are adequate protection for this species relative to uses of burrow fumigants.

Potential for Indirect Effects San Francisco
Garter Snake ( Thamnophis

sirtalis

tetrataenia )(SF GS) May Affect, Not Likely to Adversely Affect (NLAA) 1

Terrestrial prey items, riparian habitat

There is an “NLAA” determina tion for acute indirect effects due to prey reduction. The main diet of adult SFGS consists of California Red-Legged Frog (CRLF), which are listed as a threatened species (USFWS, 1985 and 2007). CRLFs also use small mammal burrows and moist leaf litter as habitat, and might be present at the time of application. US FWS has indicated measures put in place by Cal DPR are adequate protection for this species relative to uses of burrow fumigants.

48Table 7.3 Effects Determination Summary for Effects of Potassium and Sodium Nitrate Cartridges for Three Listed Species
Species Effects Basis for Determination
Determination

Potential for Direct Effects Terrestrial-phase (Juveniles and Adults) :

The fox inhabits a variety of habitats, including grasslands, grazed grasslands, shrublands, meadows, and areas of row crops, orchards and vineyards (East Contra Costa County HCP/NCCP, 2006). Although kit foxes may dig their own dens, they also modify and use those constructed by other animals (ground squirrels, badgers, and coyotes). Coyotes and ground squirrels are both target pests. The determination for potential acute direct effects is based on 100% mortality from asphyxiation based on the combustion products following application at the application site. US FWS has indicated measures put in place by Cal DP R are adequate protection for this species relative to uses of burrow fumigants.

Potential for Indirect Effects San Joaquin Kit Fox ( Vulpes

macrotis mutica ) (SJKF) May Affect, Not Likely to Adversely Affect (NLAA) 1

Terrestrial prey items, riparian habitat

There are potential acute indirect effects due to prey reduction for the SJKF consuming small mammals such as kangaroo rats, pocket mice, California ground squirrels and insects that may inhabit burrows. Some of the small mammals may also be target pests, such as ground squirrels. The prey may be present at the site of application, which results in mortality of the prey. However, USFWS has indicated measures put in place by Cal DPR are adequate protection for th is species relative to uses of burrow fumigants.

1 This species was considered in the USFWS 1993 BO an d was addressed relative to potassium and sodium nitrate cartridges in the USFWS 1996 letter to the EPA Region 9 office wherein the USFWS concurred that the Cal DPR Bulletins were adequate to address potential risk to the San Joaquin kit fox. The determination of NLAA is based upon the adequacy of the Cal DPR bulletin to protect this listed species.

497.4. Effects Determination Summary for the Critical Habitat Impact Analysis
Designated
Critical Habitat
for: Effects
Determination Basis for Determination

Almeda Whipsnake (CAW)
Habitat
Modification Lines-of-evidence indicate potential adverse effects for reduction in prey for the CAW consuming species inhabiting burrows.

The PCEs for the CAW include mammal burrows as habitat. Because the application method involves closing the burrow openings after inserting the cartridge, there would be a reduction in available shelter/cover.

EPA previously requested modification of labe ls for the Gas Cartridge and the Large Gas Cartridge based on conclusions fr om the Biological Opinion (1993) . That BO identified 17 listed species with specific mitigation for each such as time of use and geographic boundaries. In addition, memos from USFWS indicated risk to identified mammals and reptiles and included mitigation specific to the six identified species. Based on those memos, six listed species were included on labels for Dexol Gopher Gasser, SMOKE’em, and Revenge Smoke Bomb. Those modified labels provide the basi s for the current assessment.

Based on the conclusions of this assessment, incl uding additional listed species identified and the need to review geographic boundaries for current and previously iden tified listed species,
consultation will be reinitiated with the U. S. Fi sh and Wildlife Service under Section 7 of the Endangered Species Act. A screening list of endangered species with the potential to be adversely impacted by potassium nitr ate, sodium nitrate, carbon, sawdust and sulfur cartridges is provided in Appendices B-D. A ‘no effect” determination has been made for all other listed species and their critical habita t, not identified on the Appendices.

508. References

East Contra Costa County HCP/NCCP. 2006. San Joaquin Kit Fox (Vulpes macrotus mutica).Available online at: http://www.co.contracosta.ca.us/depart/cd/water/HCP/archive/hc p_nccp_content/hcp_nccp/a pp_figs/App%20D%20co mponents/App_D-02a_San_Joaquin_kit_fox_prof ile_1-18-05.pdf (Accessed on April 3, 2008).

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53

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54U.S. Fish and Wildlife Service (USFWS). 1967. Na tive Fish and Wildlife, Endangered Species. Washington, D.C. Available online at: http://ecos.fws.gov/docs/fe deral_register/fr18.pdf (Accessed on April 16, 2008).

U.S. Fish and Wildlife Servic e (USFWS). 1997. Endangered and Th reatened Wildlife andPlants; Determination of Endangered Status for the Callippe Silverspot Butterfly and the Behren's Silverspot Butterfly and Threatened Status for the Alameda Whipsnake.
Available online at: http://ecos.fws.gov/docs/federal_register/fr3183.pdf (Accessed on April 17, 2008).

U.S. Fish and Wildlife Service (USFWS), 1985. Recovery Plan for the San Francisco Garter Snake (Thamnophis Sirtalis Tetrataenia). U.S. Fish and Wildlife Service, Portland, Oregon. 77pp. Available online at http://ecos.fws.gov/docs/recovery_plan/850911.pdf

. (Accessed 24 November 2009).

U.S. Fish and Wildlife Service (USFWS), 1998. Recovery Plan for upland species of the San Joaquin Valley, California . Region 1, Portland, OR. 319 pp. Available online at http://ecos.fws.gov/docs/recovery_plan/980930a.pdf . (Accessed 24 November 2009 for the San Joaquin Kit Fox).

Westphal, M. 1998. Alameda Whipsnake: The Fastest Snake in the West. Tideline. Vol. 18 No.
2 1-3. Available online at: http://www.fws.gov/desfbay/Archives/Whip/Whip.htm (Accessed on October 3, 2007).

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