UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION 

MEMORANDUM 

DATE: November 6, 2014 

SUBJECT: 

FROM: 

Tetrachlorvinphos Response to Comments Submitted in Response to the Natural 

Resources Defense Council's April 23, 2009 Petition Requesting Cancellation of All 

Pet Uses ofTetrachlorvinphos 

Kelly Ballard, Chemical Review Manager 

Risk Management and Implementation Branch 1 

Pesticide Re-evaluation Division ~1508 P) 

THROUGH: Neil Anderson, Branch Chief ~ .J) 

Risk Management and Implementa~anch 1 

Pesticide Re-evaluation Division (7508P) 

TO: Tetrachlorvinphos Petition Docket 

Docket Number: EPA-HQ-OPP-2009-0308 

www.regulations.gov 

This memorandum serves to respond to comments that were submitted to the tetrachlorvinphos 

(TCVP) public docket (EPA-HQ-OPP-2009-0308). On June 5, 2009, the U.S. Environmental 

Protection Agency (EPA or the Agency) announced receipt of a petition, dated April 23, 2009, from 

the Natural Resources Defense Council (NRDC) that requested cancellation of all pet uses for TCVP 

in the Federal Register (74 FR 27035) and posted the petition in the public docket for a 60-day public 

comment period. The public comment period ended on August 4, 2009. During the comment period, 

EPA received approximately 8,600 form letters as part of a mass campaign supporting NRDC' s 

petition to ban TCVP pet products. In addition, the Agency also received a comment from The 

Humane Society of the United States (HSUS) that supported NRDC's Petition and a comment from 

one TCVP registrant, Hartz Mountain Corporation, which opposed NRDC's Petition. Below is a 

summary of the comments and the Agency's corresponding responses. 

Form Letter Comment: 

I urge you to cancel the pet uses of the pesticides tetrachlorvinphos and propoxur. Chemical residues 

from these products left on pet fur can damage the human brain and nervous system and cause cancer. 

Children are particularly at risk from these pesticides because their neurological and metabolic 

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systems are still developing. They are also more likely than adults to put their hands in their mouths 

after petting an animal, and so are more likely to ingest the hazardous residues. 

New testing by the Natural Resources Defense Council reveals that the EPA's decision to leave these 

products on the market may create a significant health risk to pet owners, most notably young 

children. I am therefore extremely disturbed to learn that the EPA still permits the use of these 

products on pets. The availability of many safer alternatives for flea and tick control renders the 

continued use of these pesticides in pet products an unnecessary risk. The EPA must reconsider the 

safety of these products and remove them from the market. 

I urge you to protect the health of our children as well as our pets by immediately ordering the 

removal of products containing tetrachlorvinphos and propoxurfrom the market. 

Agency Response: 

The Agency understands the concerns expressed by NRDC and the public. The Agency has addressed 

the claims presented by NRDC in a petition response, entitled Response to Natural Resources Defense 

Council's April 23, 2009 Petition Requesting Cancellation of All Pet Uses ofTetrachlorvinphos, dated 

November 6, 2014, and a new residential exposure assessment, entitled Tetrachlorvinphos: Residential 

Exposure Assessment in Response to the Natural Resources Defense Council Petition to Cancel All Pet 

Uses for Tetrachlorvinphos, dated November 5, 2014. These documents can be found in the TCVP 

public docket number EPA-HQ-OPP-2009-0308 at www.regulations.gov. 

HSUS Comment: 

These comments are being submitted on behalf ofThe Humane Society of the United States (HSUS) 

and our more than eleven million members and constituents. We thank the EPAfor the opportunity to 

comment on this dangerous chemical as it is used in flea and tick products. 

The HSUS recognizes the need to control fleas and ticks living on companion animals (dogs and cats) 

for both the welfare of these species but also for the welfare of human beings. Ensuring that the public 

has easy and economical access to products which will reduce or eliminate these ectoparasites is 

crucial to improving the quality of life for companion animals and their owners. 

Our concerns relate to the adverse reactions caused by chemicals in flea and tick products. Over the 

past decade, the HSUS has received hundreds of complaints regarding severe reactions and even 

death of companion animals caused by many flea and tick products. These pet owners are outraged by 

the lack of proof that these chemicals are safe. After losing their beloved pets and incurring enormous 

veterinary expenses trying to save their lives, these pet owners feel betrayed and confused. Despite an 

agreement between the Hartz Mountain Corporation and The EPA, The HSUS continues to receive 

complaints regarding Hartz flea and tick products more than any other manufacturer. This is not 

surprising as the EPA 's list of registered pet products containing organophosphate insecticides, which 

appears on the Natural Resources Defense Council 's website, shows that nearly all of the products 

listed under TCVP are manufactured by Hartz. 

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Even though Hartz has agreed not to sell certain products and to improve their labeling of others, The 

HSUS continues to receive complaints. Anecdotally, we were recently contacted by a constituent in 

Minnesota who had administered Hartz Flea Drops to her cat. The cat became lethargic and refused 

to eat. A visit to a veterinarian, who administered fluids and antibiotics, did not help his symptoms. 

Only after realizing that the time of the cat 's illness coincided with the application of the flea treatment 

did the owner realize what caused the cat 's decline. Unfortunately, the veterinarian did not question 

the owner if there had been a recent flea/tick treatmeni. The owner is pursuing further treatment for 

her cat, at her own expense, but larger questions remain about the safety of these products. 

We urge you to ban Tetrachlorvinphos completely for use in animals. It has likely caused significant 

harm to countless companion animals and theirfamilies and its safety in humans cannot be 

substantiated. The HSUS supports the ban of all organophosphates for use in pet products and will 

steer pet owners away from these chemicals and the companies which manufacture products 

containing them. Instead, we will encourage use of products which work to inhibit the growth of fleas 

and support flea treatment of the living environments of animals, rather than advising that chemicals 

be applied directly to animals. 

Agency Response: 

The Agency thanks HSUS for its comment expressing its concern for TCVP use on pets and potential 

adverse reactions of companion animals. The Agency shares HSUS's concern about protecting pets, 

and is committed to studying this issue more closely to understand what additional measures, if any, 

may be appropriate to reduce the incidence of these unfortunate and avoidable events. While this 

comment does not pertain to the human health issues raised by NRDC's Petition, the Agency will 

conduct an in-depth review and analysis of pet incident data resulting from pet products that contain 

TCVP during the registration review process forTCVP. 

Hartz Mou1ttain Corporation Comme1tt: 

The EPA conducted its Reregistration .E!;gibility Decision (RED) process.f()r TCVP in 2006. NRDC 

claims that EPA 'fctiled to adequately assess residential exposures to TCVP ., in the RED. However, 

l·vhile the validity (~ltesr data submilfed by NRDC in support r?f'their petilion is very questionable, most 

significant is the lack qfregulatory complhmce as noted by EPA in their l-1'riTten response to NRDC on 

lvlay 28. 2009. NRDC is required to have their study protocol reviewed by EPA ·s Human Studies 

Review Board (HSRB). which rhey.faNed to do. Without HSRB approving rhe protocol. EPA is legally 

obligated not to revieH' any data fi'om any such study. Without any data in support oft he petition the 

petition is 1vithout merit and must be denied. 

Hartz has submirted substantial daTa, including a dislodgeable residue study. to EPA in support <?l 

TCVP 's RED process. and the current uses c?f'the active ingredient in productsfor pets. The 

dislodgeable residue study supports residential exposure.findings.fhr calculating riskfi·orn use of 

companion animal insecticides. The work on the TCVP RED was completed in July 2006. 

In California. NRDC lobbied To have TCVP revie1<ved as a high priority chemica/for consideration fbr 

Prop 65 labeling requirements. In i\4ay 2009. qf.Jice (l Health Hazard Assessment (OEHHA) 

commiflee concluded that there was ins1~{jicient animal or human data to prioritize TC VP jbr a Prop 

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65 listing. This was the second time TCVP has been reviewed and not considered.f(Jr the lisling. 

OEHHA. in making their decision. revierlled all inj(Jrmationfrom the TCVP RED data, other studies 

apart.fi-om the RED and examined use patterns.f(Jr exposure in a wide list o.luses. some <?(which 

having already been voluntarily cancelled by registrants or eliminated by EPA due to exposure issues. 

Hartz is in agreement with EPA and their assessment and.findings.fl"om the TCVP RED. Hartz 

recommends EPA reject the NRDC petition due to the lack (~{'acceptable scient(/ic evidence as 

presented b,v NRDC. 

Agency Response: 

The Agency thanks Hartz for its comment, and appreciates their role in providing information to the 

Agency to refine its risk assessment related to the Petition response. 

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