Ontario Power Generation Inc. - Approval of a site-specific air standard

Instrument type: Approval of a site-specific air standard

ERO number
Ministry reference number
Notice type
Environmental Protection Act, R.S.O. 1990
Posted by
Ministry of the Environment, Conservation and Parks
Notice stage
Proposal posted
Comment period
August 30, 2022 - September 29, 2022 (30 days) Closed
Last updated

This consultation was open from:

August 30, 2022
to September 29, 2022

Proposal summary

Ontario Power Generation – Lennox Generating Station (Lennox Generating Station) has requested site-specific standards sulphur dioxide, oxides of nitrogen, and sulphuric acid for a 10-year period from (2022-2032). The ministry has reviewed this request, and proposing to issue draft site-specific standard approvals attached to this notice.

Location details

Site address

7263 33 Highway West
Bath, ON
K0H 1G0

Site location details

Ontario Power Generation - Lennox Generating Station

Site location map

The location pin reflects the approximate area where environmental activity is taking place.

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Ontario Power Generation Inc.
7263 Highway #33 West
Bath, ON
K0H 1G0

Proposal details

Proposal overview

We are working to ensure cleaner air for all Ontarians by regulating air contaminants released by industrial and commercial facilities, including Ontario Power Generation’s Lennox Generating Station (Lennox Generating Station) in Greater Napanee.

Lennox Generating Station has submitted a request to the ministry for site-specific standards for sulphur dioxide, oxides of nitrogen and sulphuric acid at the facility.

Lennox Generating Station requested one-hour site-specific standards for sulphur dioxide (SO2), oxides of nitrogen (NOx), and a 24-hour site-specific standard for sulphuric acid (H2SO4) for the Lennox Generating Station located in Greater Napanee, Ontario. This is because the Lennox Generating Station will not be able to meet the air standards for these contaminants during its periodic use of residual fuel oil when natural gas is not available.

The current Local Air Quality regulation (Reg. 419/05) sulphur dioxide (SO2) one-hour standard is 690 micrograms per cubic metres (µg/m3). On July 1, 2023 the one hour standard will be reduced to 100 µg/m3. The current Reg. 419/05 oxides of nitrogen (NOx) one-hour standard is 400 µg/m3. The current Reg. 419/05 sulphuric acid (H2SO4) 24-hour standard is 5 µg/m3. The site-specific standards requested by OPG Lennox are listed in the following table.

Contaminant Averaging Period Current Air Standard (µg/m3) Future Air Standard (µg/m3) Requested Site-Specific Standard (µg/m3)
Sulphur dioxide (SO2) 1-hour 690 100 2026 (First five years of the approval)
Sulphur dioxide (SO2) 1-hour 690 100 1430 (Remaining five years of the approval)
Oxides of nitrogen (NOx) 1-hour 400 N/A 839
Sulphuric acid (H2SO4) 24-hour 5 N/A 7.6 (First five years of the approval)
Sulphuric acid (H2SO4) 24-hour 5 N/A 5.4 (Remaining five years of the approval)


On July 9, 2021, OPG Lennox requested one-hour site-specific standards for sulphur dioxide (SO2), oxides of nitrogen (NOx), and a 24-hour site-specific standard for sulphuric acid (H2SO4) as an alternative approach to comply with the Local Air Quality regulation. This is because the Lennox Generating Station will not be able to meet the air standards for these contaminants during its periodic use of residual fuel oil when natural gas is not available.

The following information was submitted to the ministry to support Lennox Generating Station’s request:

  • a Request form - which summarizes legal information including name and location of requester, contaminant names, etc.
  • an Emission Summary and Dispersion Modelling (ESDM) Report - which includes the results from a modelling/ monitoring study and an assessment of the magnitude and frequency of exceedance of the standard(s)
  • a Technology Benchmarking Report - which assesses and ranks technical methods for reductions in contaminant concentrations and provides an assessment of feasible technologies
  • a Public Consultation Summary Report

Review of Request

The ministry has reviewed the submitted application, emissions summary and dispersion modelling report (ESDM), technology benchmarking report, a public consultation summary document, and other related documents and is considering issuing site specific standards to OPG Lennox. The proposed draft site-specific standard approvals are attached to this notice. In addition to the site-specific standard approvals, the ministry is also amending Lennox Generating Station’s Environmental Compliance Approval (ECA) to add conditions related to their operation, fuel sulphur contents, emission reduction targets, public notification and engagement, and other related information. The proposed site-specific standards approvals and corresponding amendment to the ECA require Lennox Generating Station to:

  • notify the ministry and the public when two consecutive five-minute concentrations of sulphur dioxide exceed 530 micrograms per cubic metres or when 1-hour concentration exceed 320 micrograms per cubic metres
  • ensure all new fuel purchases have a fuel sulphur content no greater than 0.5 percent
  • install and operate two monitoring stations and a meteorological tower in area where the probability of higher concentrations is expected
  • create a community liaison committee that includes local First Nations communities and Public Health representatives to provide timely information about operations and emissions
  • notify the public and ministry in advance of peak use of residual fuel oil when high emissions of sulphur dioxide and oxides of nitrogen are anticipated, and community exposure is expected and make monitoring information easily accessible to the public on a website
  • other conditions included in the proposed site-specific standard approvals and the corresponding ECA amendments

Lennox Generating Station’s action plan includes switching to a cleaner fuel with a lower sulphur content. Once fully implemented, the company expects to achieve a 40 percent reduction in sulphur emissions from the Lennox Generating Station to the surrounding community.

Regulating air contaminants in Ontario

In Ontario, we regulate air contaminants to protect communities that reside close to industrial sites. Our regulatory approach has resulted in improvements in air emissions.

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

Air standards

Our approach to improving local air quality starts with setting science-based standards to protect human health and the environment. The air standards are used to:

  • assess the performance of regulated facilities
  • identify those that need to do more to reduce their emissions

Facilities that are not able to meet an air standard due to technological or economic limitations may request a site-specific standard or a technical standard.

Site-specific standards

Site-specific standards are developed with full public transparency through public meetings and consultations. They include technology benchmarking to determine what is feasible for a company to achieve in terms of controlling emission of a contaminant over a set period (i.e. at least five years but not more than 10 years).

Compliance with a site-specific standard, just like a general air standard, must be demonstrated by using air dispersion modelling.

The ministry closely monitors the companies’ progress to ensure that the desired results are achieved.

Subsection 35(1) of the Local Air Quality Regulation (O. Reg. 419/05) includes provisions for the approval of site-specific standards and associated rules for making such requests. A site-specific standard may be approved for a period of five to 10 years. If a facility receives approval for the site-specific standard and continues to meet these requirements, then the facility is operating in compliance with O. Reg. 419/05. The site-specific standard becomes the legally enforceable standard for that facility for the time of the approval. A facility may also request a subsequent site-specific standard. Further information regarding O. Reg. 419/05 and the site-specific standard process can be accessed at the ministry website.

Additional Public Consultation

OPG conducted a public meeting in accordance with the requirements of preparing an SSS request for approval. Due to the pandemic situation, the public meeting was held virtually on June 22, 2021.

OPG consulted with affected Indigenous communities, including Mississauga Members of Williams Treaty First Nation and Mohawks of Bay of Quinte as part of the pre-consultation requirements under O. Reg. 419/05.

At Mohawks of Bay of Quinte’s request, OPG provided third-party consultants so that the community can understand the process independent of the proponent.

The ministry has contacted the local Indigenous communities to hear directly from those communities concerning any interests, comments, or questions they may have related to the proposed site-specific standards by OPG – Lennox. The ministry also contacted local public health to share the information about the proposed site-specific standard applications.

OPG’s SSS request for proposal for Lennox Generating Station is posted to the Environmental Registry of Ontario (ERO) for a minimum 30-day public consultation period because extensive pre-consultation efforts were undertaken by the ministry and the proponent, and the ministry is planning to contact the local indigenous communities during the comment period to hear directly from them.

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 Permits

40 St. Clair Avenue West
9th Floor
Toronto, ON
M4V 1M2

Office phone number


Commenting is now closed.

The comment period was from August 30, 2022
to September 29, 2022

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