Hazardous substance tax is a tax on the first possession of hazardous substances in Washington. The tax applies to petroleum products, certain pesticides, and certain chemicals.
Products subject to the hazardous substance tax (HST)
- Petroleum products.
- Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) listed substances.
- Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) registered pesticides.
Note: Minimum risk pesticides that are exempt from registration under the FIFRA 25(b) Exemption are not subject to HST.
How to pay the tax
The tax is reported on the excise tax return. There are two separate lines on the return to report each HST rate.
HST tax rate
- Non-petroleum products, or petroleum products that are not easily measured on a per-barrel basis, are subject to a rate of 0.7 % (.007) multiplied by the wholesale value of the product. For these products, use the Hazardous Substance Tax by Value line (line code 65).
- Petroleum products are subject to a rate of $1.13 per barrel (42 gallons), unless the product is not easily measured on a per barrel basis. For these products, use the Hazardous Substance Tax by Volume line (line code 81).
Tax rate per barrel*
Note: Beginning July 1, 2020, the per barrel rate on petroleum products will be adjusted for inflation on July 1 each year.
Petroleum products not easily measured on a per barrel basis
Petroleum products that remain in a liquid state at standard temperature and pressure of 25°C (or 77°F) and 1 atmosphere (or 14.7 pounds per square inch) are subject to HST on a per barrel basis. Those that do not remain in a liquid state under these conditions will continue to be taxed at a rate of 0.7 % (0.007) multiplied by the wholesale value of the petroleum product. (RCW 82.21.030 (1)(d))
Examples of products not easily measured on a per barrel basis
- Petroleum coke.
Examples of products measured on a per barrel basis
- Aviation fuel.
- Diesel fuel.
- Liquid bitumen.
- Lubricating oil.
- Bunker fuel.
These lists are not exclusive. If additional petroleum products are identified in the future, the department will add them to the applicable list. Products added to the lists will be subject to HST for all periods the tax applies, even if the product was not on the list at the time.
If you are unable to determine if a product is subject to HST using the hazardous substance lists, you may write in to the department for a ruling.
We distribute the funds to the Department of Ecology to help clean up and manage solid and hazardous wastes in the state of Washington.
Exemption from the hazardous substance tax
HST applies to the first possession of hazardous substances in Washington. Any subsequent possession of a product is exempt from HST after a Washington possessor has paid the tax.
Hazardous substance tax credits
The law describes three kinds of tax credits you may take against HST liability:
Combining hazardous substances to create a new hazardous substance
You create a new hazardous substance by combining two other kinds of hazardous substances. You may take a credit of the HST you already paid on the original two substances.
(The law allows a credit to offset this amount since you already paid HST on the first two substances).
Tax paid on fuel in fuel tanks
You may take a credit for the tax you paid on the value of fuel carried from this state in the fuel tank of airplanes, ships, trucks, or other vehicles. In effect, this gives you a tax credit for fuel that was taxed, but not used, in Washington.
Tax paid to another state
You already paid similar hazardous tax to another state. You can take Washington’s HST credit for the amount you paid to the other state. However, the hazardous tax you paid to another state must be on the same substances you bring into Washington.
Crop protection products exemption from hazardous substance tax
There is an exemption from HST by value for possession of agricultural crop protection products that you warehouse, but do not otherwise use or sell in Washington. This applies as long as you do not use, manufacture, package for sale, or sell the substance in this state.
For more information please see our Special Notice - Hazardous Substance Tax exemption for agricultural crop protection products.
Agricultural crop protection product means a chemical regulated under FIFRA as amended on Sept. 1, 2015 when used to prevent, destroy, repel, mitigate, or control predators, diseases, weeds, or other pests.
For more information please see RCW 82.21.040(5).