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  Specific waste: Warfarin

Warfarin is listed on the discarded chemicals list (Chapter 173-303-9903 WAC).  When a product with warfarin as the sole-active ingredient is discarded or not used for its intended purpose, it is a RCRA hazardous waste. 

Warfarin is the only compound that has a different RCRA listed designation, based on concentration. 

  • If the warfarin concentration is more than 0.3%, it is considered an acutely hazardous waste with a code of P001. 
  • If the warfarin concentration is less than or equal to 0.3%, it is a dangerous waste with a code of U248. 

Brand names of warfarin pharmaceuticals include: Coumadin, Jantoven, Marevan, and Waran.

Designation of waste warfarin

Warfarin tablets:  If the warfarin tablet cannot be returned to a reverse distributor for credit, it is a discarded product and a RCRA listed waste. 

  • If a tablet has warfarin as the sole-active ingredient and has a concentration of more than 0.3% warfarin (or 0.000003 mg/mg), then the waste warfarin tablet is a P001 acutely hazardous waste. 
  • If a tablet has warfarin as the sole-active ingredient and has a concentration of less than or equal to 0.3% warfarin (or 0.000003 mg/mg), then the waste warfarin tablet is a U248 dangerous waste. 
  • Any container or packaging that held a warfarin tablet that is about to be administered would not carry the RCRA listed waste codes since the tablet is removed as a product.  The container can be managed as solid waste.  Containers include foil/blister packs, bulk bottles, and paper/plastic cups to administer individual doses. For warfarin injections, see below.
  • If the tablet is determined to be a waste while still in the container, the P- and U- waste codes may apply to both the tablet and the packaging.

Warfarin for injection:  Unused or partially administered doses of injectable warfarin are considered discarded chemical product since it is not used for its intended purpose.  

  • If a liquid formulation has warfarin as the sole-active ingredient and has a concentration of more than 0.3% warfarin (or 0.000003 mg/mL), then the residual warfarin is a P001 acutely hazardous waste. 
    • If the liquid formulation is a P001 listed waste, the container is also a P001 listed waste since it is not practical to triple-rinse pharmaceutical containers, including syringes, IVs, and vials.
  • If a liquid formulation has warfarin as the sole-active ingredient and has a concentration of less than or equal to 0.3% warfarin (or 0.000003 mg/mL), then the residual warfarin is a U248 dangerous waste. 
  • Formulations where warfarin is not the sole-active ingredient are not RCRA listed waste; but you must determine if it is a RCRA characteristic waste. 

Management of waste warfarin

Viable warfarin:  Warfarin that is eligible for credit from a manufacturer, wholesaler, or reverse distributor is a viable pharmaceutical and not considered waste.  Viable pharmaceuticals include any unused and/or unopened pharmaceutical that receive a credit.  Items not receiving a credit must be managed as a waste.

RCRA hazardous warfarin waste:  This includes any non-viable formulations of warfarin and warfarin salts that designate as a listed waste (Chapter 173-303-080 WAC) or under the RCRA Characteristics of Ignitability, Corrosivity, Reactivity or Toxicity (Chapter 173-303-090 WAC). This also includes any discarded containers with warfarin residue that have not been triple-rinsed.

  • Manage as a dangerous waste at a RCRA-permitted facility. It is a violation of the Dangerous Waste Regulations to dispose of these pharmaceuticals in the sewer, sharps container, or a regulated medical waste container. 
    • Under the Dangerous Waste Regulations, accumulating more than 2.2 pounds (or 1 liter) of any P-listed waste will make you a large quantity generator. 
    • Under the Interim Enforcement Policy, the listed waste will not count towards your generator status if it is sent to a RCRA-permitted incinerator as RCRA hazardous waste on a Uniform Hazardous Waste Manifest. 

State-only dangerous waste:  You can assume any warfarin formulations that are not RCRA hazardous waste are State-only dangerous waste.  You must know the concentration of the warfarin and all other ingredients as well as the acute toxicity information of those ingredients to determine that it is not a State-only dangerous waste. 

Manage as either a dangerous waste at a RCRA-permitted facility or as excluded waste at an incinerator meeting the criteria of the conditional exclusion [Chapter 173-303-071(3)(nn)].  It is a violation of the Dangerous Waste Regulations to dispose of these pharmaceuticals in the sewer or in a sharps container or regulated medical waste container destined for landfill.