Clear as Mud: Promoting the Re-use of Liquid Soils

The Ministry of the Environment, Conservation and Parks (the “MECP”) has increased its enforcement activities against haulers of and sites that have received “liquid soil”. Enforcement activities to date have included the issuance of orders to characterize and/or remove the soil, inspections, investigations, and even quasi-criminal prosecutions.[1] Enforcement actions can result in material consequences, legal fees, and compliance costs.

This paper identifies the regulatory framework applicable to liquid soils and strategies to lawfully manage and deposit liquid soils in Ontario.

What Are Liquid Soils?

Regulatory Framework for Excess Soils

Liquid soils are a sub-category of “excess soils”, which are subject to a technical regulatory and policy framework. At the centre of this complex regulatory and policy web is O. Reg 406/19 – On-site and Excess Soil Management (the “Excess Soil Regulation”). Other instruments, including general waste management regulations under the Environmental Protection Act (the “EPA”),[2] specific soil re-use regulations,[3] municipal by-laws,[4] and conservation authority regulations,[5] also apply. The Excess Soil Regulation also incorporates various guidelines by reference, including the Rules for Soil Management and Excess Soil Quality Standards (the “Excess Soil Rules”).[6]

Liquid Soil Definition

The Excess Soil Regulation defines liquid soil as soil, crushed rock or soil mixed with rock or crushed rock with a slump of more than 150 millimetres using the Test Method for the Determination of ‘Liquid Waste’ (slump test).[7]

Slump tests are a test method to assess the likely liquid content of a material. The material is placed in a 30 cm open inverted cone, which is then removed. The slump refers to the immediate decrease in height of the material when the cone is removed.[8] Soil would be considered liquid soil when soil placed in this cone immediately decreases in height by more than 15 cm.

Liquid soils may arise from hydro excavations and the removal of sediment from stormwater management ponds. These activities will not always generate liquid soils, as it will depend on the soil profile and the water-soil ratio of any given excavation.

Deposit and Management of Liquid Soils

The Excess Soil Regulation designates excess soils as “wastes”[9]. If an exception does not apply, excess soil becomes subject to Part V of the EPA, which prohibits the management, transportation, and deposit of waste without an Environmental Compliance Approval (“ECA”) or Renewable Energy Approval.[10]

The most significant exception is where excess soil is finally deposited at a “re-use site”. For most soils, the following criteria must be satisfied:[11]

• The excess soil is directly transported to a re-use site from a project area, another re-use site, or enumerated soil processing sites;
• The re-use site owner/operator must consent in writing and if the soil is salt or asphalt-impacted, the written consent must acknowledge these impacts;
• The soil must be used for a “beneficial purpose”[12] or be governed under an instrument;[13]
• If the re-use site has an instrument, its conditions must be satisfied;
• If the re-use site does not have an instrument, the conditions in Section 5 of the Excess Soil Regulation must be satisfied, including that the soil is of an appropriate quality as determined under the Excess Soil Rules.

The Excess Soil Regulation introduces additional regulatory hurdles for liquid soils. To overcome these hurdles, a person must do one or more of the following:

• Deposit the liquid soil at a re-use site governed by an instrument that authorizes the deposit of liquid soil.[14] This step may limit the number of eligible receiving sites.[15]
• A person may “process” or manage liquid soil at the “project area”[16], through passive dewatering or mixing the soil with additives to dewater or solidify the soil.[17]
• Re-use the liquid soil at any of the following locations and comply with the criteria in the Excess Soil Regulation and the Excess Soil Rules:
  • the project area;
  • a related project area forming part of a single larger initiative;[18] or
  • if the soil was from an infrastructure project, a related infrastructure project;[19] or
• Transport the soil to an approved site for treatment or disposal.[20]

These additional steps can add additional material costs and complexity to projects, creating further regulatory hurdles to the construction of much-needed infrastructure and housing. In light of the significant benefits associated with activities that often leant to the creation of liquid soils and the low risks associated with these soils, the authors respectfully suggest that future amendments to the Excess Soil Regulation should promote the greater re-use of liquid soil in a manner that remains consistent with the EPA’s environmental protection objectives.

Any article or other information or content expressed or made available in this Section is that of the respective author(s) and not of the OBA.