Proposed Re-evaluation Decision PRVD2015-05, d Phenothrin

Notice to Reader:

The online consultation is now closed.

Pest Management Regulatory Agency
19 June 2015
ISSN: 1925-0967 (PDF version)
Catalogue number: H113-27/2015-5E-PDF (PDF version)

This page is a summary of the consultation document. If you would like to comment, please request the full consultation document.

To obtain a full copy of Proposed Re-evaluation Decision PRVD2015-05, d-Phenothrin please contact our publications office.

Should you require further information please contact the Pest Management Information Service.


Table of Contents

What Is the Proposed Re-evaluation Decision?

After a re-evaluation of the insecticide d-phenothrin, Health Canada's Pest Management Regulatory Agency (PMRA), under the authority of the  Pest Control Products Act and  Regulations, is proposing continued registration for the use and sale of d-phenothrin products in Canada.

An evaluation of available scientific information found that products containing d-phenothrin do not present unacceptable risks to human health or the environment when used according to the proposed label directions. As a condition of the continued registration of d-phenothrin, new risk-reduction measures are proposed for the end-use products registered in Canada. No additional data are being requested at this time.

This proposal affects all end-use products containing d-phenothrin registered in Canada. Once the final re-evaluation decision is made, registrants will be instructed on how to address any new requirements.

Proposed Re-evaluation Decision PRVD2015-05, d-Phenothrin is a consultation document that summarizes the science evaluation for d-phenothrin and presents the reasons for the proposed re-evaluation decision. It also proposes new risk-reduction measures to further protect the environment.

Proposed Re-evaluation Decision PRVD2015-05, d-Phenothrin is presented in two parts. The Overview describes the regulatory process and key points of the evaluation, while the Science Evaluation provides detailed technical information on the assessment of d-phenothrin.

The PMRA will accept written comments on this proposal up to 45 days from the date of publication of Proposed Re-evaluation Decision PRVD2015-05, d-Phenothrin. Please forward all comments to Publications.

What Does Health Canada Consider When Making a Re-evaluation Decision?

The PMRA pesticide re-evaluation program considers potential risks, as well as value, of pesticide products to ensure they meet modern standards established to protect human healthand the environment. Regulatory Directive DIR2012-02, Re-evaluation Program Cyclical Re-evaluation, presents the details of the current re-evaluation approach.

For more details on the information presented in this summary, please refer to the Science Evaluation section of Proposed Re-evaluation Decision PRVD2015-05, d-Phenothrin.

What Is d-Phenothrin?

The insecticide d-phenothrin is a synthetic pyrethroid insecticide used to control a broad range of arthropod pests on a wide variety of sites, including in and around structures, indoor and outdoor ornamental plants and mattresses. This insecticide is also used as flea and tick control products. It works by contact and stomach action, and is fast acting. It is applied by members of the general public and professional applicators using an applicator tube, pressurized spray can or shaker can.

Health Considerations

Can Approved Uses of d-Phenothrin Affect Human Health?

The insecticide d-phenothrin is unlikely to affect your health when used according to label directions.

Potential exposure to d-phenothrin (sumithrin technical grade) may occur through the diet (food and water), when handling and applying the product, or when entering treated sites. When assessing health risks, two key factors are considered: the levels at which no health effects occur and the levels to which people may be exposed. The dose levels used to assess risks are established to protect the most sensitive human population (for example, children and nursing mothers). Only uses for which the exposure is well below levels that cause no effects in animal testing are considered acceptable for registration.

Toxicology studies in laboratory animals describe potential health effects from varying levels of exposure to a chemical and identify the dose at which no effects are observed. The health effects noted in animals occur at doses more than 100 times higher (and often much higher) than levels to which humans are normally exposed when pesticide-containing products are used according to label directions.

In laboratory animals, the technical grade active ingredient d-phenothrin was slightly acutely toxic by the inhalation route of exposure. It was of low acute toxicity by the oral and dermal routes, minimally irritating to the eyes, not irritating to the skin, and did not cause an allergic skin reaction.

There was no evidence to suggest that d-phenothrin damaged genetic material and it is not considered to be a potential human carcinogen. Although d-phenothrin exerts its action on the nervous system, there was little evidence of neurotoxicity. There was no indication that d-phenothrin caused damage to the immune system or affected the ability to reproduce. Health effects in animals given repeated doses of d-phenothrin included effects on the liver, adrenals and kidneys.

When given to pregnant or nursing rats, d-phenothrin caused slight, transient decreases in body weight of the young animal at doses that were not toxic to the mother, suggesting that the young were slightly more sensitive to d-phenothrin than the adult animal. Effects on the developing fetus (malformations) were noted following administration of d-phenothrin to pregnant rabbits. These effects occurred at doses that were also toxic to the mother.

The risk assessment protects against the effects of d-phenothrin by ensuring that the level of human exposure is well below the lowest dose at which these effects occurred in animal tests.

Residues in Food and Drinking Water

Dietary risks from food and water are not of concern.

Reference doses define levels to which an individual can be exposed over a single day (acute) or lifetime (chronic) and expect no adverse health effects. Generally, dietary exposure from food and water is acceptable if it is less than 100% of the acute reference dose or chronic reference dose (acceptable daily intake). An acceptable daily intake is an estimate of the level of daily exposure to a pesticide residue which, over a lifetime, is believed to have no significant harmful effects.

There are no agricultural uses of d-phenothrin in Canada. The only possible source of residue in the Canadian diet would be from imported food commodities from indirect applications to food commodities.

Acute and chronic dietary exposures to d-phenothrin were estimated from potential residues of d-phenothrin from imported commodities. Exposures were assessed for different subpopulations including children and women of reproductive age.

The acute dietary exposure estimate (from food and drinking water) at the 99.9th percentile was less than 1% of the acute reference dose for the general population and for all population subgroups. The chronic dietary exposure estimate for the general population and for all population subgroups was less than 1% of the acceptable daily intake. Thus, acute and chronic dietary risks are not of concern.

The  Food and Drugs Act prohibits the sale of adulterated food, that is, food containing a pesticide residue that exceeds the established maximum residue limit. Pesticide maximum residue limits are established through the evaluation of scientific data under the Pest Control Products Act. Each maximum residue limit value defines the maximum concentration in parts per million (ppm) of a pesticide allowed in or on certain foods. Food containing a pesticide residue that is at or below the established maximum residue limit does not pose a health risk concern.

Since there are no Canadian or international food uses of d-phenothrin, maximum residue limits have not been specified. Where no specific maximum residue limit has been established, subsection B.15.002(1) of the Food and Drug Regulationsapplies, which requires that residues not exceed 0.1 ppm. Additional details regarding maximum residue limits can be found in the Science Evaluation section of this consultation document.

Risks in Residential and Other Non-Occupational Environments from d-Phenothrin

Non-occupational risks are not of concern when d-phenothrin is used according to label directions.

Residential exposure may occur from the application of products containing d-phenothrin to residential gardens and trees, indoor environments, and pets. Homeowner exposure would occur from applying domestic-class d-phenothrin products. These products can be applied by aerosol can, shaker can and spot-on treatments (pets).

Residential postapplication exposure may occur while performing activities on treated areas. Treated areas include areas treated by residential handlers as well as residential areas treated by commercial applicators. Exposure would be predominantly dermal and by inhalation. Incidental oral exposure may also occur for children (1 to < 2 years old) playing in treated areas or in contact with treated dogs.

For all domestic-class products, the target dermal and inhalation margins of exposure (MOEs) were met for adults applying d-phenothrin and are not of concern. Residential postapplication activities also met the target dermal and inhalation MOEs for all populations and are not of concern. For incidental oral exposure, the target oral MOE was met for children (1 to < 2 years old) and are not of concern.

Incidental oral scenarios were aggregated with background (chronic) dietary exposure (food and drinking water). The resulting aggregate risk estimates reach the target MOE for all uses and are not of concern.

Occupational Risks from d-Phenothrin

Occupational risks are not of concern when d-phenothrin is used according to label directions.

The calculated dermal and inhalation MOEs are greater than the target MOE for all of the commercial applicator scenarios using baseline personal protective equipment. As such, no additional mitigation measures are required for these scenarios. The MOEs were calculated using the highest application rate of all of the commercial products.

It was assumed that risks to postapplication workers would be similar to or less than residential postapplication risks. As no risks of concern were identified for residential postapplication scenarios, a specific assessment for postapplication workers was not required.

Environmental Considerations

What Happens When d-Phenothrin Is Introduced Into the Environment?

The insecticide d-phenothrin is used primarily in and around homes as a domestic insecticide. Based on this use pattern, environmental exposure is expected to be minimal. It can enter soil and surface water if released into the environment. This insecticide is non-persistent in soil, breaking down in the presence of microbes. In water, d-phenothrin is broken down rapidly by sunlight and microbes and, consequently, is not expected to persist in aquatic environments. The insecticide d-phenothrin is not expected to enter the atmosphere and be subject to long-range transport. Laboratory studies indicate that d-phenothrin is not likely to move downward through the soil, indicating that it has a low potential to leach to ground water.

The insecticide d-phenothrin poses negligible risk to terrestrial birds and mammals. At high enough doses, it can be toxic to terrestrial and aquatic invertebrates and fish. However, due to its use pattern, the potential exposure of terrestrial and aquatic non-target organisms is expected to be minimal; consequently, the risk to these organisms is not of concern.

Proposed Measures to Minimize Risk

Labels of registered pesticide products include specific instructions for use. Directions include risk-reduction measures to protect human health and the environment. These directions must be followed by law. As a result of the re-evaluation of d-phenothrin, the PMRA is proposing further risk-reduction measures for product labels.

Human Health

As no risks of concern were identified for d-phenothrin, no additional mitigation measures are required. However, revisions to the labels are proposed to provide consistency across common products, update label statements and minimize unnecessary exposure. The proposed label amendments are listed in Appendix VIII of Proposed Re-evaluation Decision PRVD2015-05, d-Phenothrin.


Due to the limited outdoor use of d-phenothrin, the risk to terrestrial and aquatic organisms is expected to be minimal. However, precautionary statements are being proposed to further protect the environment. The proposed label amendments are listed in Appendix VIII of Proposed Re-evaluation Decision PRVD2015-05, d-Phenothrin.

Next Steps

Before making a final re-evaluation decision on d-phenothrin, the PMRA will consider all comments received from the public in response to Proposed Re-evaluation Decision PRVD2015-05, d-Phenothrin. A science-based approach will be applied in making a final decision on d-phenothrin. The PMRA will then publish a Re-evaluation Decision that will include the decision, the reasons for it, a summary of comments received on the proposed decision and the PMRA's response to these comments.

Report a problem or mistake on this page
Please select all that apply:

Thank you for your help!

You will not receive a reply. For enquiries, contact us.

Date modified: