are inert ingredients in pesticide formulations?
The pest control product that you buy at a store
or have applied by a professional is a formulated
product. This means it includes both the active
ingredient used to control pest and formulating
ingredients such as emulsifiers and solvents, sometimes
called "inerts," that are not involved directly
in controlling the pest but provides other benefits.
Inert ingredients, also called formulants, are materials
intentionally added to the formulation to modify
or improve physical characteristics such as, sprayability,
solubility, spreadability, stability or solvency.
The vast majority of inert ingredients,
or formulants, are common industrial chemicals used
every day in the home.
They are found in products such as cleansers, furniture
strippers, kitchen and bathroom disinfectants, shampoos
When a registration application for a pesticide
is received, scientists at Health Canada examine
the toxicity potential of all ingredients in the
product, as well as specific toxicity data generated
for the active ingredient. In addition, manufacturers
must submit acute toxicity tests on all formulations.
Health Canada officials review these data, as well
as the identity of the formulants. Any indication
from these studies that the formulants are enhancing,
or in some way altering the toxicity of the pesticide
active ingredient, may require further studies before
regulatory officials will register the formulated
What do the experts say about
2,4-D is the most common pesticide used by homeowners
and is considered safe by experts based on hundreds
of studies including long-term exposure studies
in agricultural or industrial settings. The weight
of scientific evidence on the safety of 2,4-D has
been considered by numerous experts including a
panel convened by the U.S. Environmental Protection
Agency (1994) and expert panels from the Canadian
Centre for Toxicology (1987, 1992), who concluded
that the overall evidence does not indicate that
2,4-D poses health risks to humans when used as
directed. The European Commission stated that "there
is no clear association between cancer development
and exposure to phenoxy herbicides (including 2,4-D
and 2-EHE) could be established from the available
epidemiological studies". How can one rationalize
that 2,4-D is "less safe" if used to control weeds
on lawns than to control some of the same weeds
on a farm field for food production?
Canada's Pest Management Regulatory Agency
(PMRA) does not permit the use of inert ingredients
known to have toxicological concern in any
Canadian pesticide product. Registration must
be obtained from Health Canada before the
formulation is allowed to be sold.