Ecology has received a new request to use Imidacloprid to control burrowing shrimp

We are evaluating a new application requesting permission to use the pesticide Imidacloprid to control burrowing shrimp in Willapa Bay and Grays Harbor. The application was filed by about a dozen oyster farmers from the Willapa Grays Harbor Oyster Growers Association, who propose to use the pesticide to treat tide lands to support their aquaculture practices.

We are now in the process of evaluating the environmental impacts of the proposal — which we will request your comments and suggestions on when we issue our draft environmental report at the end of this summer.

Similar to previous permit request 

This request for a permit is similar to — but not the same as — an earlier permit application to use Imidacloprid to control burrowing shrimp. The previous permit application process ended in 2015, but following public concern over the permit, the growers withdrew it, and the permit was never used.

About a dozen of the oyster growers from the earlier permit process have now applied for a new permit.

Environmental review

Diagram of permit process. for more information contact Rich Doenges at

Process to complete environmental review and permit application processing.
Click image to see larger version.

We are evaluating this proposal to understand the negative impacts it could have on the environment. We’re preparing an additional environmental study to inform our decision of whether to deny the permit application or to develop a draft permit approval.

We prepared an Environmental Impact Statement for the 2015 permit process, and we will supplement it with the most up-to-date research and information available. We will develop what’s called a Supplemental Environmental Impact Statement – it will build on the environmental review from 2015.

Where are we in the environmental review process?

We’re still early in the review process. Right now we are analyzing new research and information that wasn’t available to us when we prepared the 2015 Environmental Impact Statement. This will go into a new draft report, which we will publish for public review and comments.

Even though we’re not ready for official public comments yet, we encourage anyone who wishes to share their views on the applications, or Ecology’s action moving forward, to contact us. Also, if you have information you want to ensure we consider for our supplemental environmental review, please send it to us.

Please visit our website for more information.

Public comment period

Once we have a draft Supplemental Environmental Impact Statement prepared, we’ll open a 45-day public comment period. This will be the time to review and comment on the draft environmental report. We’ll also host several public meetings on the draft report in key locations across western Washington.

We will use what we learn during the public comment period to finalize the Supplemental Environmental Impact Statement. This is a crucial step in our environmental review required under the State Environmental Policy Act (SEPA).

What’s changed since the previous permit request?

This is a new request for a permit, but we’re building on information learned from the 2015 process. Some examples of new or different information we are taking into consideration include:

  • Acreage
    Today, there are fewer farmers applying for a permit. The applicants propose treating less acreage — 485 acres in Willapa Bay and 15 acres in Grays Harbor — as opposed to 2,000 acres across the two bays in the previous permit. 
  • Method
    The method of applying the pesticide has changed. The growers propose spraying Imidacloprid from boats or ground equipment rather than helicopter. 
  • Best available science
    The U.S. Environmental Protection Agency (EPA) released a new risk assessment on the environmental impacts of Imidacloprid, and neonicotinoids, generally, in December 2016. Health Canada and the European Food Safety Authority have also recently released similar risk assessments. This and other new research will contribute to our supplemental environmental review. 

Our role regulating Washington’s environment

Ecology regulates the quality of Washington’s waters. Any discharges of pollution to state waters must obtain a permit from the federal EPA called the National Pollution Discharge Elimination System permit. EPA delegates the responsibility of managing these requests within Washington to Ecology. The purpose of this permit is to ensure that pollution does not rise to a level which causes harm to people or the environment.

Sediments contain much of the aquatic life that makes up the base of the food web essential to healthy estuaries. These organisms are important food for salmon, sturgeon, and many other species. Beyond affecting just the overlying water, this permit request to use Imidacloprid to control burrowing shrimp will impact the sediment where the pesticide is applied.

Because of this, the growers applying for the permit must also get two Sediment Impact Zones approved. This is to ensure the proposed use doesn’t violate Washington Sediment Management Standards. The permit and Sediment Impact Zone determinations combined will address requirements necessary to protect Willapa Bay and Grays Harbor for a multitude of uses.

If we authorize Sediment Impact Zones — one for Willapa Bay and one for Grays Harbor — we would set requirements for how:

  • Imidacloprid may be applied to the sediment
  • The applicants ensure that the impact is contained only to the designated zones
  • The area is monitored after the discharge occurs

The state Sediment Management Standards protect Washington’s benthic environment. That is, we recognize that it’s important to protect both the overlying waters and the grounds underneath. These rules work to reduce — and ultimately eliminate — sources of pollution that harm the ecosystem and make people sick.

aerial view down at a bay with the airplane wing at the edge of the photo.

A view of scenic Willapa Bay from our marine monitoring research program.
Photo by: Christopher Krembs/Ecology

Working toward a healthier Washington

A cornerstone of work at Ecology is to continually reduce pollution, and to work toward more protective permit conditions.

For this specific permit to be issued, a process called Integrated Pest Management must be followed. This is the practice of continually working toward managing burrowing shrimp more sustainably, and without chemicals. We have been supportive of research into alternative control methods and will continue to support future efforts.

Stay informed

You can follow this permitting process and get the most up-to-date information by subscribing to our Aquatic Pesticide Permits listserv or checking our Burrowing Shrimp Control webpage frequently. We will also publish updates to our blog as we have new information.