Hazardous Substance Tax.
The hazardous substance tax (HST) is a tax on the first possession of hazardous substances in Washington. The HST applies to petroleum products, certain pesticides, and certain chemicals and is generally imposed on a per-barrel basis. For fiscal year 2026, the tax rate on petroleum products is $1.48 per barrel. Non-petroleum products, including insecticides and pesticides, as well as petroleum products that are not easily measured, are subject to a rate of 0.7 percent multiplied by the wholesale value of the products. Any subsequent possession of a product is exempt from the HST after a Washington possessor has paid the tax.
Hazardous Substance Tax Exemption for Agricultural Crop Protection Products.
There is an exemption from the HST for businesses that store agricultural crop protection products (insecticides and pesticides) that are later sold out of state. Eligible insecticides and pesticides are:
The exemption expires January 1, 2028.
Tax Preference Performance Statement.
Tax preferences confer reduced tax liability upon a designated class of taxpayers. These include tax exclusions, deductions, exemptions, preferential tax rates, deferrals, and credits. There are over 700 tax preferences. Legislation that establishes or expands a tax preference must include a tax preference performance statement (TPPS) that identifies the public policy objective of the preference, as well as specific metrics that the Joint Legislative Audit and Review Committee (JLARC) can use to evaluate the effectiveness of the preference. All new tax preferences automatically expire after 10 years unless an alternative expiration date is provided.
The expiration date of the HST exemption for agricultural crop protection products is extended to January 1, 2038.
A TPPS, 10-year expiration, and JLARC review are included with a TPPS policy objective to incentivize businesses to store agricultural pesticides in Washington as the products are engaged in interstate commerce.