Supplemental Information To

Nalco, Inc.’s Request that EPA Reconsider Its Registration for Ammonia 

Products as Precursors to Chloramine Used in Water Treatment and Provide 

Assurance that there is No Risk of Enforcement During the Reconsideration 

and Any Necessary Transition Period

July 7, 2008

Introduction

The following information is supplemental to Nalco’s December 4, 2007 request that EPA 

reconsider its registration for ammonia products and is in response to the Agency’s July 3, 2008 

request for additional explanation. Specifically, the Agency requested:

· a definition of “activator”

· an explanation of why Nalco believes that each compound identified in 

Appendix 3 of its December 4, 2007 request compares to the role it believes 

ammonia has when used in conjunction with chlorine to treat water and to 

Nalco’s request

Explanation of the Term “Activator”

There is no regulatory definition for the term “activator” when associated with pesticides. The 

term is used loosely by the Agency and the industry to refer to a non-pesticidally active 

compound used in conjunction with a non-pesticidally active precursor chemical that is required 

to result in the formation of a pesticidally active ingredient. An example of the Agency’s use of 

the term “activator” is provided in Nalco’s December 4, 2007 request on page 10 as follows:

For example sodium bromide is a registered precursor which calls for the use of an 

activator. See Reregistration Eligibility Decision for Inorganic Halides, Case 4051 (Sep. 

1993) (“The sodium bromide solution usually is mixed with activators such as chlorine 

gas, calcium hypochlorite [ ], sodium hypochlorite [ ], potassium monopersulfate [ ], and 

ozone.”). “Sodium bromide per se is a stable salt with no pesticidal activity.” Id. at 10. 

When mixed with an activator, “the active disinfectant, [ ] hypobromous acid,” is 

produced. Id. “[H]ypobromous acid is an effective microbiological control treatment,” 

“oxidiz[ing] organic and inorganic material present in effluent water.”

A similar situation exists for generation of chlorine dioxide from the precursor sodium chlorite or 

sodium chlorate. In the case of both sodium bromide and sodium chlorite or sodium chlorate, 

there is no pesticidally active ingredient prior to activation. The activator is needed to generate 

the active ingredient.

EPA registers pesticide precursors only in circumstances where registering the precursor is the 

only means by which the Agency could regulate the production and use of pesticides generated 
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at the point of application. Therefore, EPA registers precursors when they are the “only logical 

chemical[s] through which the use of a pesticide can be regulated.” In the Matter of South Coast 

Chemical, Inc., 2 E.A.D. 139 (March 11, 1986). The Agency has not required the registration of 

activators themselves used with the precursor compounds, as explained by Nalco in its December 

4, 2007 request.

Ammonia Used with Chlorine Is Not an Activator

When used with chlorine compounds for water treatment, ammonia is not an “activator” (as that 

term is used by the Agency). The chlorine compounds themselves are pesticidally active, and 

there is no need for ammonia to produce a pesticidally active compound. As explained by Nalco 

(see at Section III of Nalco’s December 4, 2007 request), the use of ammonia with chlorine 

compounds actually reduces the pesticidal activity of the chlorine compounds. Ammonia is not a 

precursor to any pesticidally active compound, nor is it needed for the pesticidal activity of the 

EPA-registered chlorine compounds. As explained by Nalco, ammonia extends the time that 

chlorine compounds remain active in the system by slowing the rate of chlorine reaction and 

deactivation in the water treatment systems. As a direct result, the need for chlorine-containing 

inputs is reduced.

Thus, as Nalco explained, ammonia acts more in the manner of a sequestrant, i.e., “preventing or 

inhibiting normal ion behavior by combination with added materials” (The American Heritage 

Dictionary of the English Language, Fourth Edition, published by Houghton Mifflin Company). 

There is no regulatory definition of “sequestrant” associated with pesticides. 

The Agency Has a Long-Standing Practice of Not Requiring Registration of Compounds 

that Are Not Pesticidally Active and Are Not Precursors to Pesticidally Active Compounds 

But Which Modify the Activity of Pesticidally Active Compounds

Because there are no regulatory definitions associated with pesticides for terms such as 

“sequestrant,” “activator,” “intensifier,” “neutralizer,” “stabilizer,” “deactivator,” and similar 

terms, these terms are used imprecisely by the Agency and registrants. However, the Agency 

clearly has a long-standing practice of not requiring registration for compounds modify the 

activity of or interact with the pesticidally active ingredient, as long as such compounds are not 

essential as precursors to a pesticidally active compound.

The compounds identified by Nalco in Appendix 3 of its December 4, 2007 request are simply 

publicly available examples of compounds that the Agency has determined to be inert 

components of pesticide products when the description of the purpose of the inert component 

indicates that it will modify the activity of or interact with the pesticidally active ingredient in the 

formulation. In all cases, the description of the purpose of the inert formulant indicates a 

modification of activity, either to improve the activity (synergist, intensifier, catalyst) or modify 

(slow or increase) the rate of degradation or availability (buffer, sequestrant, chelation, 

antioxidant, release rate regulator, neutralizer, antioxidant, pH control, reducer, safener, 

stabilizer). In all cases, the description suggest a chemical reaction, but not one that is needed to 

produce a pesticidally active ingredient.
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The Agency has confirmed that compounds with such actions, if not a component of a pesticide 

formulation but sold separately from the pesticide product, are not subject to FIFRA even when 

intended to be used with a pesticide product (70 FR 31401, June 1, 2005). As components of 

pesticide products, compounds with the types of actions identified above are considered as inert 

ingredients, generally referred to as adjuvants.

Ammonia used in water treatment systems along with EPA-registered chlorine-based products is 

an adjuvant (sequestrant), acting solely to reduce the rate of bioavailability and reduce the rate of 

degradation of the active ingredient chlorine. Ammonia is not pesticidal and does not act as a 

precursor to a pesticidally active compound.

In summary, ammonia does not have independent antimicrobial activity, nor is it necessary to 

generate a pesticidally active ingredient; instead, it is used with chlorine compounds, that are 

pesticidally active without any “activation” by ammonia or any other component.. In fact, 

ammonia prolongs the availability of chlorine, either as free chlorine or as chloramines. EPA 

has consistently held that products that provide this type of stabilization function for pesticides 

are not required to be registered under FIFRA.