Cette consultation a eu lieu :
du 13 mai 2026
au 12 juin 2026
Résumé de la décision
This ministry has approved site-specific air standards for chromium compounds (hexavalent) for the Owens Corning Composite Materials Canada LP, Guelph Glass Plant (Owens Corning Guelph) in Guelph, Ontario that expire on December 31, 2031.
Détails de l'emplacement
Adresse du site
247 York Road
Guelph,
ON
N1E 3G4
Canada
Détails de l'emplacement du site
Owens Corning Composite Materials Canada GP Inc., as general partner for and on behalf of Owens Corning Composite Materials Canada LP, Guelph Glass Plant.
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Owens Corning Composite Materials Canada GP Inc.
247 York Road
Guelph,
ON
N1E 3G4
Canada
Détails de la décision
Decision overview
Our government is committed to protecting Ontario’s air quality and ensuring we have strong environmental standards that protect human health and the environment. As part of this commitment, the ministry is working to ensure cleaner air for all Ontarians by regulating air contaminants.
Following a 30-day public consultation period, the ministry has approved annual site-specific standards for chromium compounds (hexavalent) for Owens Corning Composite Materials Canada LP, Guelph Glass Plant (Owens Corning Guelph) located in Guelph, Ontario, expiring on December 31, 2031. The approved site-specific standards for chromium compounds (hexavalent) for Owens Corning Guelph can be found in the supporting materials section below.
In association with this site-specific standard approval, a number of new terms and conditions are included in the facility’s environmental compliance approval to reduce the off-site concentrations of chromium compounds (hexavalent) and manage potential risks to the community.
By phasing in increasingly stringent limits on concentrations of chromium compounds (hexavalent), the ministry is requiring Owens Corning Guelph to implement and expedite actions to progressively reduce annual off-site concentrations from current levels over the duration of the approval. Owens Corning Guelph’s action plan to reduce off-site levels of chromium compounds (hexavalent) includes modifications to the exhaust stacks serving the glass melting furnace and the forehearth to improve contaminant dispersion and continuing to review the technical feasibility and potential effectiveness of add-on control technologies.
Action Plan Items and anticipated completion dates:
- By December 31, 2026:
- re-engineer the forehearth stack - install additional fan to increase the exhaust velocity
- By December 31, 2027:
- re-engineer the forehearth stack - increase stack height and modify the exhaust velocity, if necessary
- re-engineer the glass melting furnace stacks – install additional fans to increase the exhaust velocity of each stack and increase stack height, if necessary
- By December 31, 2031:
- complete a review of technical feasibility of installing add-on controls for reducing emissions of chromium compounds (hexavalent) from the facility, supported by submission of an engineering report by September 30, 2029
Chromium Compounds (Hexavalent) Site-Specific Standard (annual averaging period) approval:
- 0.00133 micrograms per cubic metres - from July 1, 2026 to December 31, 2026
- 0.00084 micrograms per cubic metres - from January 1, 2027 to December 31, 2027
- 0.00069 micrograms per cubic metres - from January 1, 2028 to December 31, 2031
Chromium Compounds (Hexavalent) Environmental Compliance Approval Amendments:
Amendments have also been made to Owens Corning Guelph’s Environmental Compliance Approval to include terms and conditions related to the site-specific standards that include (see ERO # 026-0514 for the Environmental Compliance Approval (ECA) decision notice):
- source testing requirements for chromium compounds (hexavalent) to accurately estimate emissions from the facility and to demonstrate ongoing performance/ compliance
- source testing requirements for total chromium and particulate to aid the evaluation of the technical feasibility of add-on controls and technology benchmarking
- reporting requirements regarding glass melting operations
- requirements for public reporting on the status of the action plan implementation and emissions reductions over time
- a requirement to prepare and submit to the ministry an engineering report to evaluate the technical feasibility of installing add-on controls for reducing emissions of chromium compounds (hexavalent) from the facility
Background
Owens Corning Composite Materials Canada LP operates the Guelph Glass facility (“the facility”) in Guelph, Ontario. Chromium compounds (hexavalent) are released to the atmosphere from glass melting operations at the facility, resulting from molten glass flowing through vessels containing chromium-based refractory brick.
Owens Corning Guelph previously requested and received a site-specific standard approval for chromium compounds (hexavalent) in 2016 (https://ero.ontario.ca/archive/012-5061) which expires on June 30, 2026.
In 2025, Owens Corning Guelph submitted a request to the ministry for another annual site-specific standard for chromium compounds (hexavalent) of 0.00133 micrograms per cubic metres as the facility is still not able to comply with the general air standard for this contaminant. The current general annual air standard for chromium compounds (hexavalent) is 0.00014 micrograms per cubic metres.
The requested site-specific standard value was calculated using an air dispersion model (AERMOD) and represents the maximum predicted concentration that can occur in the vicinity of the facility when emissions are at maximum levels and coincide with meteorological conditions that result in the highest predicted ground level concentration. The maximum predicted concentration occurs along the Owens Corning Guelph facility property line with lower concentrations (still above the air standard) predicted in nearby residential areas.
The Owens Corning Guelph site-specific standard request included an action plan to modify the exhaust stacks serving the glass melting furnace and the forehearth to improve contaminant dispersion, continue to review the technical feasibility and potential effectiveness of add-on control technologies (milestone 1), and potentially make process modifications which could affect discharges of chromium compounds (hexavalent) afterwards (milestone 2). Owens Corning Guelph proposed to complete this action plan over a period of 10 years and noted that the most significant portion of the reduction in concentrations of chromium compounds (hexavalent) at points of impingement is expected with the implementation of milestone 1.
The ministry has reviewed this request and posted decisions, as set out in the supporting materials section below, for site-specific air standards for chromium compounds (hexavalent) for a total duration of 5.5 years (with expiry date of December 31, 2031). The duration of the site-specific standards reflects the ministry’s opinion that the elements of milestone 1 of the action plan can be completed in a 5.5-year period and that the elements outlined in milestone 2 of the action plan do not significantly reduce levels beyond what will be achieved from milestone 1. Further, the proposed technical feasibility review of add-on control technologies can also be appropriately conducted within the 5.5-year period.
During the 5.5-year approval period, Owens Corning Guelph will be required to meet increasingly stringent site-specific air standards to reflect the phased implementation of the facility’s action plan, resulting in reduced contaminant concentrations in the surrounding community over time.
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 (Ontario Regulation 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
We are working to ensure cleaner air for the people of Ontario by regulating air contaminants released into communities by local industrial and commercial facilities, including Owens Corning Guelph.
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 register to 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 emissions 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 (Ontario Regulation 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 meets that standard, the facility is operating in compliance with Ontario Regulation 419/05 (O. Reg. 419/05). The site-specific standard becomes the legally enforceable standard for that facility for the time of the approval. Prior to expiry, 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. https://www.ontario.ca/page/rules-air-quality-and-pollution
Effets de la consultation
Public consultation by the ministry on the proposed site-specific standards was provided through an Environmental Registry of Ontario (ERO) posting for 30 days, from May 13, 2026 to June 12, 2026. As a result of this public consultation, the Director received 1 comment submission and 1 email correspondence. All questions and comments submitted regarding this proposal were considered.
The following is an overview of 3 common themes that were raised and the ministry’s response to each.
Comment #1: Request for clarity on how the Ministry’s requirement for an engineering review of additional add-on controls is expected to build upon previous technical feasibility assessments and what new information it is expected to be provided in support of future decision-making and health protection. Owens Corning has already operated under a site-specific standard for ten years and had undertaken multiple emissions reduction initiatives and technical evaluations during that period.
Response: Owens Corning Guelph's site-specific standard request submitted in 2025 included a technology benchmarking report that identified best available controls for chromium compounds (hexavalent) and concluded that more research is required into the feasibility and potential effectiveness of add-on controls before it can be considered for installation at the facility. Owens Corning Guelph also proposed in their action plan to continue to review the technical feasibility and potential effectiveness of add-on control technologies that are implemented at similar facilities in other jurisdictions.
Consequently, the ministry is requiring Owens Corning Guelph to retain an appropriately qualified independent professional engineer to prepare an engineering report, evaluating the technical feasibility of add-on controls (such as an electrostatic precipitator or other equivalently effective and commercially available dust control technology) for the purposes of reducing the emissions of chromium compounds (hexavalent) from the glass melting equipment at the facility. The report is to include an analysis that considers all relevant data associated with the operation of the glass melting equipment at the facility, consistent with good engineering practice, based on the current furnace operating conditions and emissions data obtained from the annual source testing, which is also required by conditions related to the site-specific standard approval.
The engineering report must be prepared and submitted to the Ministry no later than September 30, 2029 to ensure that the findings in the report regarding the technical feasibility of these add-on controls are available for Owens Corning Guelph and the Ministry to consider before the expiry of the site-specific standard approval of December 31, 2031. This report may assist Owens Corning Guelph in evaluating and potentially implementing best available control technology to further reduce contaminant emissions from the facility. This supports the ministry’s future decision-making with the objective to reduce air pollution levels in the surrounding community for human health protection and to ensure that any future site-specific standard, if necessary, is also set at the minimum difference necessary from the general air standard.
Comment #2: Request for some clarity on how the proposed 5.5-year approval period was determined from a health-protection perspective, including how the timeline balances expected exposure reductions, technical feasibility and the Ministry’s conclusion that later action plan elements are not expected to significantly reduce concentrations beyond milestone 1. Consideration should be given to the demonstrated trajectory of improvement achieved under the original site-specific standard, ambient monitoring results and the feasibility of achieving additional reductions within a longer timeframe.
Response: The ministry’s decision to approve the site-specific standard for chromium compounds (hexavalent) for the Owens Corning Guelph facility over a 5.5-year period is intended to drive improvements in air quality in a technically feasible manner within a reasonable time period, so that the site-specific standard approval results in the minimum difference necessary from the general air standard.
The Owens Corning Guelph action plan proposed to improve the dispersion of contaminants from the exhaust stacks serving glass melting operations and to continue to review the technical feasibility and potential effectiveness of add-on control technologies (milestone 1). Later actions were proposed to potentially make process modifications which could affect discharges of chromium compounds (hexavalent) afterwards (milestone 2). These actions were proposed to be completed over a 10-year period with the most significant reduction in concentrations of chromium compounds (hexavalent) occurring after the implementation of milestone 1
The ministry has reviewed the steps set out in milestone 1 of the action plan and concluded that these items can be implemented within a 5.5-year period. During the 5.5-year approval period, the site-specific standard becomes more stringent over time to ensure that Owens Corning Guelph is implementing its proposed action plan as quickly as feasible to reduce air contaminant concentrations and exposures in the local community. Further, the proposed technical feasibility review of add-on control technologies can also be appropriately conducted within the 5.5-year period. After completing the technical feasibility review and depending on the outcome of that review, Owens Corning Guelph may be able to take additional steps to include add-on controls, if technically feasible, to further reduce contaminant emissions from the facility.
With respect to the items outlined in milestone 2 of the action plan, Owens Corning Guelph predicted that milestone 2 could potentially reduce the maximum off-property concentration of chromium compounds (hexavalent) by a minor amount (from 0.00069 to 0.00068 micrograms per cubic metre). In the ministry’s view, this minor reduction in the concentration of chromium compounds (hexavalent) and the uncertainties surrounding the implementation of add-on control, does not justify the additional length of time requested for the site-specific standard.
From a health-protection perspective, the ministry’s technical review of the Owens Corning Guelph request was undertaken alongside the health risk interpretation of the proposed site-specific standard value. The ministry’s review concluded that the proposed site-specific standards of chromium compounds (hexavalent) fall within the ministry’s risk management framework where levels require further reductions to manage potential risks in the local community. While the ministry recognizes the improvements achieved by Owens Corning Guelph since the original site-specific standard issued in 2016, the ministry’s objective is to continually improve local air quality by working with Owens Corning Guelph to drive strategies to reduce their emissions and work towards achieving compliance with the health‑protective air standard.
Comment #3: Comments that support the Environmental Compliance Approval amendment related to source testing, operational reporting and public engagement. Comments commending Owens Corning Guelph’s efforts, research and community engagement that has taken place.
Response: The ministry acknowledges this comment supporting the environmental compliance approval terms and conditions for source testing and public reporting and also acknowledges the efforts of Owens Corning Guelph to engage with the community and improve local air quality over the past many years. The ministry continues to oversee Owens Corning Guelph’s progress to improve air pollution levels in the community through continuous improvement to ensure they are achieving the desired results towards meeting the general air standard for chromium compounds (hexavalent).
Documents justificatifs
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1 Stone Road West
Floor 4
Guelph,
ON
N1G 4Y2
Canada
40 St. Clair Avenue West
9th Floor
Toronto,
ON
M4V 1M2
Canada
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Contact
Jeff Burdon
40 St. Clair Avenue West
9th Floor
Toronto,
ON
M4V 1M2
Canada
Proposition initiale
Détails de la proposition
Background
Owens Corning Composite Materials Canada LP operates the Guelph Glass facility (“the facility”) in Guelph, Ontario. Chromium compounds (hexavalent) are released to the atmosphere from glass melting operations at the facility, resulting from molten glass flowing through vessels containing chromium-based refractory brick.
Owens Corning Guelph previously requested and received a site-specific standard approval for chromium compounds (hexavalent) in 2016 (https://ero.ontario.ca/archive/012-5061) which expires on June 30, 2026. In 2025, Owens Corning Guelph submitted a request to the ministry for another site-specific standard for chromium compounds (hexavalent) for a duration of 10 years as the facility is still not able to comply with the general air standard for this contaminant. The Owens Corning Guelph request included an action plan to re-engineer the exhaust stacks serving the glass melting furnace and the forehearth to improve contaminant dispersion and to continue to review the technical feasibility and potential effectiveness of add-on control technologies for a period of 10 years.
The ministry has reviewed this request and is proposing to approve a site-specific air standard for chromium compounds (hexavalent) for a 5.5-year period. The site-specific standard is proposed to become increasingly stringent over the 5.5-year period. The proposed site-specific standard approval is attached in the Supporting Materials section of this notice.
Request Overview
Owens Corning Guelph is requesting a site-specific standard for chromium compounds (hexavalent) of 0.00133 micrograms per cubic metres (annual average) for a duration of 10 years. The requested site-specific standard value was calculated using an air dispersion model (AERMOD) and represents the maximum predicted concentration that can occur in the vicinity of the facility when emissions are at maximum levels and coincide with meteorological conditions that result in the highest predicted ground level concentration. The maximum predicted concentration occurs along the Owens Corning Guelph facility property line with lower concentrations (still above the air standard) predicted in nearby residential areas. Exceedance of an air standard does not mean that adverse effects will occur, but rather that the risk of such effects increases with the concentration, frequency and duration of exposure.
The ministry's current annual air standard for chromium compounds (hexavalent) is 0.00014 micrograms per cubic metres. It is derived from lifetime cancer risks associated with continuous exposure and corresponds to an incremental risk of 1‑in‑a‑million (10⁻⁶), which is considered negligible. The air standard is aimed at minimizing long‑term inhalation exposure to reduce cancer risk while also providing protection against other potential health effects.
Chromium compounds (hexavalent), also known as hexavalent chromium, is a toxic form of chromium that poses health risks, particularly through inhalation. It can damage genetic material (DNA), which underlies its carcinogenicity. Exposures to hexavalent chromium at high concentrations, well above the ministry’s air standard, can also cause non‑cancer effects mainly affecting the respiratory tract and lung function. Impacts on the kidneys, liver, immune system, and skin can occur with prolonged exposure to significantly elevated concentrations.
The Owens Corning Guelph site-specific standard request included an action plan to modify the exhaust stacks serving the glass melting furnace and the forehearth to improve contaminant dispersion, continue to review the technical feasibility and potential effectiveness of add-on control technologies (milestone 1), and potentially make process modifications which could affect discharges of chromium compounds (hexavalent) afterwards (milestone 2). Owens Corning Guelph proposed to complete this action plan over a period of 10 years and noted that the most significant portion of the reduction in concentrations of chromium compounds (hexavalent) at points of impingement is expected with the implementation of milestone 1.
Review of request
The ministry has reviewed the Owens Corning Guelph request and is proposing to approve a site-specific air standard for chromium compounds (hexavalent) for a total duration of 5.5 years. The duration of the proposed site-specific standards reflects the ministry’s opinion that the elements of milestone 1 of the action plan can be completed in a 5.5-year period and that the elements outlined in milestone 2 of the action plan do not significantly reduce levels beyond what will be achieved from milestone 1. Further, the proposed technical feasibility review of add-on control technologies can also be appropriately conducted within the 5.5-year period. The proposed approval includes increasingly stringent site-specific standard levels over the duration of the 5.5-year approval to reflect the phased implementation of the facility’s action plan, resulting in reduced contaminant concentrations in the surrounding community over time.
The proposed site-specific standard approval is attached in the Supporting Materials section of this notice.
Proposed Chromium Compounds (hexavalent) Site-Specific Standard approval:
- 0.00133 micrograms per cubic metres - from July 1, 2026 to December 31, 2026
- 0.00084 micrograms per cubic metres - from January 1, 2027 to December 31, 2027
- 0.00069 micrograms per cubic metres - from January 1, 2028 to December 31, 2031
Chromium Compounds (hexavalent) Environmental Compliance Approval Amendments
In addition to the proposed site-specific standard approval, the ministry is also proposing to amend Owens Corning Guelph’s Environmental Compliance Approval (ECA) to add terms and conditions related to chromium compounds (hexavalent) emissions that include:
- source testing requirements for chromium compounds (hexavalent) to accurately estimate emissions from the facility and to demonstrate ongoing performance/ compliance
- source testing requirements for total chromium and particulate to aid the evaluation of the technical feasibility of add-on controls and technical benchmarking
- reporting requirements regarding glass melting operations
- requirements for public reporting on the status of the action plan implementation and emissions reductions over time, and
- a requirement to prepare an engineering report to evaluate the technical feasibility of installing add-on controls for reducing emissions of chromium compounds (hexavalent) from the facility
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 (O. Reg. 419/05: Air Pollution - Local Air Quality) works within the province's air management framework to address contaminants released to air in communities by various sources, including industrial and commercial facilities.
Air standards
We are working to ensure cleaner air for the people of Ontario by regulating air contaminants released into communities by local industrial and commercial facilities, including Owens Corning Guelph.
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 register to a technical standard.
Site-specific standards
Site-specific standards are developed with 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 emissions of a contaminant over the period of the approval.
Compliance with a site-specific standard, just like a general air standard, must be demonstrated by using air dispersion modelling.
The ministry closely oversees 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 requests for site-specific standards and associated rules for making such requests. A site-specific standard may be set for a period of five to 10 years. If a facility receives a site-specific standard and meets that standard, 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 period of the site-specific standard. 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 (https://www.ontario.ca/page/rules-air-quality-and-pollution).
Other public consultation opportunities
Owens Corning Guelph shared information regarding their site-specific standard request through their public liaison committee meeting in January 2025. A summary of the feedback received during that meeting was provided in the Public Consultation Report included with the request submitted by Owens Corning Guelph.
Documents justificatifs
Consulter les documents en personne
Certains documents justificatifs peuvent ne pas être accessibles en ligne. Si tel est le cas, vous pouvez demander à consulter les documents en personne.
Veuillez communiquer avec le bureau mentionné ci-dessous pour savoir si les documents sont accessibles.
1 Stone Road West
Floor 4
Guelph,
ON
N1G 4Y2
Canada
40 St. Clair Avenue West
9th Floor
Toronto,
ON
M4V 1M2
Canada
Commentaire
La consultation est maintenant terminée.
Cette consultation a eu lieu 13 mai 2026
au 12 juin 2026
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Jeff Burdon
40 St. Clair Avenue West
9th Floor
Toronto,
ON
M4V 1M2
Canada
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