Department of Ecology News Release - January 5, 2018
Updated: January 4, 2018

Environmental review completed for imidacloprid

Report evaluates impacts of using pesticide to control burrowing shrimp

Photo of Willipa Bay.
SOUTH BEND  –  After considering public input and conducting a thorough environmental assessment, the Washington Department of Ecology has completed the final environmental review on a proposal to use the pesticide imidacloprid to control burrowing shrimp.
Shellfish growers from Willapa Grays Harbor Oyster Growers Association (WGHOGA) have requested a permit to use the pesticide imidacloprid on burrowing shrimp in Willapa Bay and Grays Harbor. Ecology’s findings have been adopted in a formal report, called a Final Supplemental Environmental Impact Statement. This review adds to the initial Environmental Impact Statement adopted in 2015.

Supplemental environmental review findings:
  • Significant impacts to sediment quality and benthic invertebrates.
  • Adverse impacts to juvenile worms and crustaceans in the areas treated with imidacloprid and the nearby areas covered by incoming tides.
  • Concern about non-lethal impacts to invertebrates in the water column and sediment.
  • New information shows a risk of impacts from imidacloprid even at low concentrations.
  • Likely indirect impacts to fish and birds if food sources are disrupted.
  • Little known direct risk to fish, birds, marine mammals, and human health.
  • Increased uncertainty about long-term, non-lethal, and cumulative impacts.
  • Continued knowledge gaps about imidacloprid.
Ecology will use these findings to inform the agency’s decision on the pending permit application. The agency anticipates announcing a decision in about a month.
The report compiles what Ecology learned by reviewing the best available science on this proposal and the public input received during a 45-day public comment period. Ecology received 8,287 comments on the draft of this report.
See the final report and learn more on our website at   

Contact information

Jessica Payne