About hazardous waste

Hazardous waste is waste that, when present in quantities and concentrations that are high enough, pose a threat to human health or the environment if they are improperly stored, transported, treated or disposed.

Hazardous waste is primarily generated by industrial and manufacturing processes, and includes a broad range of materials such as:

  • materials from manufacturing (e.g., waste acids, contaminated sludges and chemicals)
  • biomedical wastes from hospitals and other health care facilities
  • waste solvents
  • waste pesticides
  • polychlorinated biphenyls (PCBs)
  • industrial lubricants and oils containing heavy metals perchloroethylene (perc) waste from dry cleaners
  • discarded batteries

Hazardous waste requires special handling with respect to how it is collected, stored, transported, treated, recovered and disposed to reduce adverse effects to human health and the environment.

The Made-in-Ontario Environment Plan commits to making producers responsible for the waste generated from their products and packaging to encourage new, innovative and cost-effective ways to recycle products and lower costs for consumers. The Municipal Hazardous or Special Waste Program is scheduled to transition to the producer responsibility model on December 31, 2020.

Source law

You can find a complete set of rules related to managing hazardous and liquid industrial wastes at:

Hazardous Waste Program regulatory proposal consultation

We consulted on a discussion paper for 60 days from June 19, 2020 to August 18, 2020, which outlined a possible approach to modernizing hazardous waste reporting in Ontario. This feedback informed the development of two new regulatory proposals, which have been posted to the Environmental Registry of Ontario for public comment:

If approved, these proposed regulations will eliminate outdated processes and help make hazardous waste reporting simpler, faster and more cost-effective.
We are now looking for your feedback on these proposals. The deadline for submissions is 11:59 p.m. on November 2, 2020.

Manage hazardous wastes

The Ministry of the Environment, Conservation and Parks has a cradle-to-grave management system for subject waste which controls:

  • collection
  • storage
  • transportation
  • treatment
  • recovery
  • disposal

Subject waste is a term used to identify the types of waste that must be registered with the ministry. It includes:

  • liquid industrial waste (LIW)
  • hazardous waste, including hazardous waste treated to remove characteristic hazards such as reactivity and ignitability

Some specific types of waste are exempt from the definition of subject waste. This means you do not have the registration or manifesting requirements that apply to other hazardous waste and LIWs.

A generator is the operator of a waste generation facility. Generators include:

  • the original generator of the waste (e.g., operators of commercial and manufacturing facilities that produce waste)
  • the operator of waste disposal, transfer, bulking or processing facility that forwards materials off-site for subsequent waste management
  • a municipal hazardous or special waste (MHSW) depot
  • other types not listed

Generator registration

All subject waste generators must register on the Hazardous Waste Information Network (HWIN) to provide the government with a record of:

  • who creates hazardous waste
  • where it is generated
  • what hazardous wastes they generate

HWIN is an online generator registration and manifesting system for generators, carriers and receivers of subject waste.

HWIN provides generators of subject waste with:

  • a convenient way to handle their annual registration
  • the ability to pay their annual registration fee
  • electronic manifesting to record and track the movement of subject waste from the generator through to final disposal

Facility operators need to determine if they produce or accumulate subject waste that falls under Ontario’s generator registration requirements. For more information on registration requirements, visit:

For assistance with generator registration, manifesting and other HWIN related questions, please contact:

HWIN Help Desk
Monday to Friday (8 a.m. to 5 p.m.)
1-866-494-6663 (toll-free)


All off-site movement of hazardous waste and liquid industrial waste is tracked using a manifest.

The manifest:

  • accompanies the waste from its point of origin to its point of disposal
  • describes the waste
  • shows when it changes hands between generators, carriers and receivers


If you are a carrier or receiver of hazardous waste or liquid industrial waste, you must obtain Environmental Compliance Approvals from the Ministry of the Environment, Conservation and Parks outlining the specific conditions of your operations, including wastes you are approved to manage safely.

Get an environmental compliance approval

Waste classes are included in an approval for waste carriers or receivers to identify the waste streams they are permitted to handle or manage.

In Ontario, there are 53 waste classes that are identified by a three-digit number. Each number is assigned to a generic waste description that is used to classify the type of waste being managed.

Please refer to the registration guidance manual for more information on how to correctly choose a waste class and characterize your wastes.

Updated: August 30, 2021
Published: March 20, 2014