Mini-Mills Industry Standard

ERO number
Notice type
Environmental Protection Act, R.S.O. 1990
Posted by
Ministry of the Environment, Conservation and Parks
Notice stage
Proposal Updated
Proposal posted
Comment period
November 29, 2022 - January 28, 2023 (60 days) Closed
Last updated

Update Announcement

This notice was originally published on November 29, 2022 for a 45 day comment period ending January 13, 2023. The notice was republished on January 6, 2023 to extend the deadline to submit comments to January 28, 2023.

This consultation was open from:

November 29, 2022
to January 28, 2023

Proposal summary

We are proposing a technical standard for mini mills industry to help ensure facilities that produce steel from scrap steel better control their air emissions and will align with similar standards and environmental practices of other provinces and countries, such as the United States.

Proposal details

Proposal Overview

The Ministry of the Environment, Conservation and Parks is working to ensure cleaner air for all Ontarians by regulating air contaminants released by industrial and commercial facilities.

We are proposing a new technical standard for the mini mills sector in Ontario to help ensure facilities that produce steel from scrap steel better manage their air emissions.

Under a technical standard, facilities will be required to implement best available technologies and best practices for their sector to help them reduce the risk to public health, while allowing them to continue to operate responsibly in a transparent manner.

This proposed technical standard is aligned with similar standards and environmental practices use by comparable facilities in other provinces and countries, such as the United States.

We invite feedback from the public, municipalities, First Nations, environmental groups, and industry on our proposed technical standard so that we can continue to protect air quality and create tailored solutions that address the unique challenges in our communities.

Technical standards in Ontario

A technical standard is a technology-based solution designed for facilities in an industry sector that are not able to meet an air standard for one or more contaminants due to technical limitations or economic challenges. It helps better control, monitor, and/or manage local air emissions.

There are two types of technical standards:

  • industry standards regulate all sources of a specified contaminant(s) within an industry sector
  • equipment standards address a source of contaminant, but may apply to one or multiple industry sectors.

When the government develops a technical standard, a review of best available controls and best practices used in other leading jurisdictions (e.g. other Canadian provinces and the US) is undertaken to identify the best available technology and practices that should be adopted by Ontario for the sector.

Once a technical standard is published, any facility in the sector may ask to be registered under that standard.

Proposed Mini Mills industry standard

The proposed industry standard:

  • includes the following six contaminants discharged from a mini mill facility:
    • chromium compounds (hexavalent)
    • chromium compounds (metallic, divalent and trivalent)
    • manganese and manganese compounds
    • nickel and nickel compounds
    • suspended particulate matter
    • dioxins, furans and dioxin-like polychlorinated biphenyls (PCBs).
  • would apply to mini mill facilities identified as part of North American Industry Classification System (NAICS) code 331110 that primarily produce steel using an electric arc furnace and exclude integrated iron and steel mills that do not.

The dominant sources of key contaminants from this sector consist of:

  • the mini mill melt shop including electric arc furnaces, ladle refining furnaces, argon oxygen decarburization vessels and industrial ventilation
  • slag management including slag processes such as cooling, crushing, screening, handling and storage
  • alloy additive material management
  • scrap management including processing, handling, and storage, and
  • on-site roads.

Key proposed requirements include:

  • industrial ventilation requirements to capture and move emissions from the melt shop furnaces and vessels to required air pollution control technology, and more stringent requirements for new and/or significant modifications to melt shop furnaces and vessels, industrial ventilation and air pollution control technology
  • operating, monitoring, assessment, inspection and maintenance requirements
  • best practices and technologies for the management of outdoor fugitive emissions from sources such as slag management and on-site roads requirements to assess the performance of best practices with visual inspections and “near-source” monitoring that triggers additional action to manage outdoor fugitive emissions
  • requirements to make operational adjustments (when deviations occur)
  • requirements to maintain existing air pollution controls and management methods at the facility (even if it is not specified in the proposed technical standard)
  • complaint response, public reporting, notification and recordkeeping requirements.

Read more about the proposed requirements in the draft rationale document and the proposed Mini Mills - Industry Standard.


In 2013, mini mill companies asked us to develop a technical standard, for the new and updated metals air standards that came into effect on July 1, 2016.

We have been working with the mini mill companies since 2013 as part of a technical committee.

Facilities have submitted abatement plans that include implementing key aspects of the proposed technical standard aimed at improving operational practices and preparing for the technical standard.

Embedded in the proposed Mini Mills - Industry Standard are a combination of compliance approaches that link together to form a strategy to ensure:

  • facilities are required to have best available technologies and best practices with greater accountability for compliance and driving continuous improvement
  • for key requirements, facilities are required to notify the ministry and when necessary the ministry follows up, to ensure oversight, and
  • company officials are made aware of the facility’s performance such as any operational issues through annual summary reports that are signed by the highest-ranking individual at the facility with management responsibilities.

Purpose of Policy:

The primary objective of a technical standard is to set requirements for the industry to use the best available air pollution control or best practices. This will help modernize operations and reduce air emissions.

In practical terms, a technical standard provides a set of rules that include air pollution control requirements and/or best practices that focus on key contributors to off-site concentrations of air toxics. A facility that meets its obligations under a technical standard is in compliance with the regulation.

When we develop a proposed technical standard, we:

  • compare representative facilities in the sector to other similar facilities operating in other jurisdictions to determine whether similar requirements can be set for Ontario facilities.
  • review the specific sources of contaminant(s) and determine the dominant sources that impact the local community, benchmark technologies and best management practices to address these sources, and consider economic issues that relate to the sector.

Regulating air contaminants in Ontario

Ontario's Local Air Quality Regulation (O. Reg. 419/05: Air Pollution - Local Air Quality) works within the province's air management framework by regulating air contaminants released into communities by various sources including local industrial and commercial facilities.

Ontario has a unique regulatory approach to improving local air quality that starts with setting science-based standards to protect human health and the environment. While these standards may not always be achievable due to limitations in technology or economics, the goal is to reduce emissions through continuous improvement and best available technologies and practices over time.

Some facilities that are not able to meet an air standard may request a site-specific or technical standard. These standards require companies to invest in the best available technologies and modern air pollution controls and practices to reduce air emissions and improve air quality over time.

We closely oversee the companies' progress to ensure they are achieving the desired results.

Improvements in addressing air emissions have been achieved as a result of our regulatory approach.

Site-specific and technical standards are developed with full public transparency through public consultation. We consult the public on all applications for site-specific and technical standards and public input plays an integral role in the ministry's review of proposals.

Read more about the rules on air quality and pollution in Ontario

Supporting materials

View materials in person

Some supporting materials may not be available online. If this is the case, you can request to view the materials in person.

Get in touch with the office listed below to find out if materials are available.

Local Air Quality Section

40 St. Clair Avenue West
7th & 9th floor
Toronto, ON
M4V 1M2

Office phone number


Commenting is now closed.

The comment period was from November 29, 2022
to January 28, 2023

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