Diazinon was safe, now it isn't



December 5, 2000

TO: Garden writers

FR: Sean Gray, Environmental Working Group Pesticide Policy Analyst

New EPA decision phasing out diazinon

Within the last six months, the U.S. Environmental Protection Agency
(US EPA) has sharply restricted the nation's #1 and now #2 home use
insecticides, Dursban and diazinon. Both these chemicals are
organophosphates, or nerve gas derivatives, and the EPA determined
that they were too dangerous to use in the home and especially around
children. But, the removal of Dursban and diazinon from the
marketplace means gardeners nationwide will be asking you about better
ways to keep unwanted pests out of their garden.

So, how can your readers protect their gardens from bugs?

While organic gardening is a sustainable alternative, gardeners might
still want synthetic pesticides for a variety of reasons. The best
answer is to use a pesticide specific to the insect rather than a
massive application of a powerful toxin. For specific problems that
cannot be solved without synthetic chemicals, there are a variety of
new "reduced risk" and bio-pesticides. These new pesticides are
usually safer for humans and affect only the target pest (and closely
related organisms). The EPA is currently in the process of creating a
web site with information about these reduced risk pesticides, but it
won't be ready until sometime in 2001.

As an example, the EPA suggested alternatives for dealing with
termites after the decision to ban Dursban. Their list included some
of the "reduced risk" pesticides mixed with some pyrethroids and
synthetic pyrethroids. (However, we should note that pyrethroids
should not be used near open water due to acute toxicity to
shellfish.) The EPA recommended anything from the following list for
termites: permethrin, cypermethrin, imidacloprid, fipronil,
bifenthrin, esfenvalerate, deltamethrin, cyfluthrin, or bait systems
using sulfluramid, hexaflumeron, diflubenzuron, or hydramethylnon.

For non-synthetic and organic alternatives, the Northwest Coalition
for Alternatives to Pesticides has created fact sheets of non-chemical
alternatives for a variety of different pest problems. These should be
your first source when responding to questions about alternatives to
Dursban and diazinon. The information is available online at
http://www.pesticide.org/factsheets.html, and there is also a link on
our website, http://www.ewg.org.

Despite their popularity, Dursban and diazinon have now been
determined unsafe for the men, women, children, and infants who come
into contact with them. This contradicts the repeated safety
assurances over the years from EPA and the pesticide industry. If
Dursban and diazinon are unsafe now, then they've ALWAYS been unsafe.
If the 1996 Food Quality Protection Act (FQPA), the law that ordered
the systematic safety evaluation of each pesticide, had been in place
in the 1940's when these pesticides were introduced, they never would
have been registered.

Dursban and diazinon belong to the family of insecticides known as
organophosphates (OPs). OPs were derived from World War II chemical
warfare and act as neurological toxins on insects, mammals, and even
humans. In humans, they inhibit the production of an enzyme, acetyl
cholinesterase, which keeps your brain and nervous system functioning
smoothly. Minor exposures may lead to headaches, nausea, dizziness,
weakness, and drowsiness. More serious exposure can cause comas,
seizures, and death. Infants and children are especially at risk to
low doses because relatively small doses of OP pesticides can affect
nervous system development.

Since OPs work on individual organisms, effective use requires heavy
and repeated applications of the insecticide. These repeated broad
application techniques lend themselves to excessive human exposure
even when following the package directions. For example, in the
Preliminary Occupational and Residential Risk Assessment for Diazinon
published by the EPA, application of diazinon by a home gardener
provided exposures up to 3500 times a "safe" dose (20x for a push
spreader, 288x for a spray wand, and 3500x for applying with a
paintbrush).

Even though today's agreement will allow diazinon to be manufactured
until 2003, we don't think the risks of diazinon to home gardeners,
their families and their pets are worth it. We recommend all gardeners
stop using products containing the chemical immediately. We hope you
will urge your readers to do the same.