Independent Environmental Monitoring Program: McMaster Nuclear Reactor
| Site name | McMaster Nuclear Reactor |
|---|---|
| Licensee | McMaster University (McMaster) |
| Facility name | McMaster Nuclear Reactor |
| Facility location | Hamilton, Ontario |
| Land acknowledgement | The CNSC acknowledges that the McMaster Nuclear Reactor is located within the traditional territory of the Haudenosaunee and Anishnaabe Nations. |
| Facility description | McMaster operates an open-pool research reactor housed in a stand-alone containment building located on the McMaster University campus in Hamilton, Ontario. It has been in operation since 1959 and provides neutron-based services in support of applications in health, materials, energy, and environmental sciences. |
| Environmental protection requirements | In accordance with regulatory requirements under the Nuclear Safety and Control Act, all licensees must maintain a comprehensive environmental protection program to monitor and control nuclear and hazardous substances released from the facilities they own and operate. As part of every licensee’s environmental protection program, concentrations of contaminants in the environment must be determined and the potential exposure routes to the public must be assessed and mitigated. |
Our Independent Environmental Monitoring Program (IEMP) results from 2023 and 2025 are consistent with the results submitted by McMaster, supporting our assessment that the licensee’s environmental protection program is effective. The results add to the body of evidence that people and the environment in the vicinity of the McMaster Nuclear Reactor are protected and that there are no anticipated health impacts from the operation of the facilities on the site.
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Results
2025
The 2025 IEMP sampling plan for the McMaster Nuclear Reactor focused on radioactive nuclear substances. A site-specific sampling plan was developed based on the licensee’s approved environmental monitoring program and our regulatory experience with the site. We endeavour to incorporate traditional Indigenous land use, values and knowledge by engaging with Indigenous Nations and communities on the sampling plan. More information on this engagement is provided in the “Indigenous Nations and communities’ participation” section.
In May 2025, we collected air and soil samples in publicly accessible areas outside the facility perimeter. The levels of radioactivity measured in air and soil were below levels specified in available guidelines as well as our own screening levels. Our screening levels are based on conservative assumptions about the exposure that would result in a dose of 0.1 mSv/year (one-tenth of the regulatory public dose limit of 1 mSv/year). Measurements conducted through the IEMP to date have consistently found levels of radioactivity in the environment to be low, and well within the range of natural background radiation levels. As a result, no effects on human health are expected as a result of the McMaster Nuclear Reactor’s operations.
2023
The 2023 IEMP sampling plan for the McMaster Nuclear Reactor focused on nuclear substances. A site-specific sampling plan was developed based on the licensee’s approved environmental monitoring program and our regulatory experience with the site. We endeavour to incorporate traditional Indigenous land use, values and knowledge by engaging with Indigenous Nations and communities on the sampling plan. More information on this engagement is provided in the “Indigenous Nations and communities’ participation” section.
In May 2023, we collected samples in publicly accessible areas outside the facility perimeter.
The levels of radioactivity measured in air and soil were below available guidelines and our own screening levels. Our screening levels are based on conservative assumptions about the exposure that would result in a dose of 0.1 mSv per year (one-tenth of the regulatory public dose limit of 1 mSv per year). The measurements indicate that the levels of radioactivity in the environment are low and well within the range of natural background radiation levels. As a result, no effects on human health are expected.
1 The reference samples are taken in a location where there is likely no potential for exposure from the operations of the nuclear facility. The reference location is chosen based on distance from the operation, on meteorological data such as predominant wind direction or precipitation (for atmospheric releases) and water current (for effluent discharges). This allows us to collect local data that is representative of the region around the facility. This data is then compared with sampling results. This is especially important when background data, guidelines or screening levels do not exist for a certain contaminant or medium in a certain region.
Indigenous Nations and communities’ participation
We have made it a priority to ensure that IEMP sampling reflects Indigenous knowledge, land use and values where possible. In addition to conducting routine IEMP sampling activities, we seek input from local Indigenous Nations and communities on our IEMP sampling plans.
In advance of the 2025 IEMP sampling campaign around the McMaster Nuclear Reactor, emails were sent to Indigenous Nations and communities with interest in the facility to notify them of the sampling campaign and to seek input on the sampling plan. We invited suggestions for species of interest, valued components, and potential sampling locations where traditional practices and activities may take place.
The Six Nations of the Grand River reviewed the draft sampling plan and did not have any feedback.
We will continue to engage with interested Indigenous Nations and communities to ensure that IEMP sampling incorporates Indigenous knowledge, values and priorities in future sampling.
Focus on health
We review the results of public health reports and data, international publications, and at times conduct our own health studies to provide additional confidence that the health of people living near the McMaster Nuclear Reactor is protected. The City of Hamilton Public Health Services (Hamilton Public Health), Public Health Ontario, and Cancer Care Ontario (CCO) monitor the health of populations around Hamilton. Disease rates are compared to rates in populations that are demographically/geographically similar, or to larger reference populations such as Ontario, to detect any potential health outcomes that may be of concern.
According to Hamilton’s Community Health Status Report (2024), ischemic heart disease, dementia and Alzheimer disease, cerebrovascular diseases, chronic lower respiratory diseases, and cancer (particularly lung and colorectal) are the leading causes of death. These are followed by unintentional poisoning (primarily from opioid overdoses), for which rates are rising.
Similar to the general populations of Canada and Ontario, the most diagnosed cancer types in Hamilton are lung, colorectal, breast and prostate. According to CCO, cancer incidence rates (i.e., new cases per year) from 2016 to 2020 were higher in Hamilton compared to rates in Ontario for all cancers combined. This was also the case for Hamilton’s rates of colorectal, liver and lung cancer and melanoma, while the incidence rates in Hamilton for leukemia, prostate and thyroid cancers were lower than those in the rest of Ontario.
Health data often varies by region, and the opportunity to be healthy is not the same for everyone; it is affected by personal, lifestyle, social, economic, environmental and systemic factors. The Hamilton population is diverse in gender, sexual orientation, race, education, income, housing status, and social supports. Hamilton Public Health recognizes that health inequities exist and is committed to finding opportunities for improvement.
According to Hamilton’s 2024 report, nearly half of all premature deaths among Hamilton residents in 2021 were considered preventable and mainly caused by tobacco, alcohol, and opioids. Tobacco smoking, a known risk factor for many types of cancer, is common in the region, but declined between 2015-16 and 2019-20. According to CCO, a higher percentage of Hamilton’s population is overweight or obese compared to the rest of Ontario, being overweight or obese is also a risk factor for cancer. Additionally, cancer screening for breast and colorectal cancer is lower in Hamilton compared to Ontario.
We are all exposed to natural sources of ionizing radiation from several sources, including the earth’s atmosphere and crust. The 2024 Cross-Canada Radon Survey reported that 12% of houses in Hamilton are exposed to radon levels above Health Canada’s guideline of 200 Bq/m3. Similarly, the Hamilton Household Radon Survey (2019–20) found that approximately 14% of participating homes exceeded Health Canada’s guideline.
Health status data for Indigenous people was not included in Hamilton’s 2024 Community Health Status Report, and is not reported separately by Hamilton Public Health. According to a 2017 report co-published by CCO, of the most common cancers among First Nations people in Ontario, the incidence rates of lung, colorectal, and kidney cancers were higher compared to other people in Ontario. This report also indicated that deaths from cancer were higher among First Nations people compared to other people in Ontario.
Based on current levels of radionuclides in the environment, exposures to people living in the area, the current scientific knowledge about the sources, effects, and risks of ionizing radiation, and relevant local, provincial, and federal health data, we have not observed and do not expect to observe any adverse health outcomes related to the presence of the McMaster Nuclear Reactor.
For additional information, please visit the following websites:
- Hamilton Public Health Services
- Hamilton's Community Health Status Report 2024
- Radon – City of Hamilton
- 2024 Cross-Canada Radon Survey
- Ontario Cancer Statistics 2022 – Cancer Care Ontario
- Cancer in First Nations People in Ontario – 2018 Report
- Ontario Cancer Profiles – Cancer Care Ontario
- CNSC Health Studies – lists relevant CNSC, national and international studies
Conclusions
Our IEMP results from 2023 and 2025 are consistent with the results submitted by McMaster, supporting our assessment that the licensee’s environmental protection program is effective. The results add to the body of evidence that people and the environment in the vicinity of the McMaster Nuclear Reactor are protected and that there are no anticipated health impacts from the operation of the facilities on the site.
Related links
Other monitoring programs and reporting
CNSC regulatory oversight reports
Frequently asked questions IEMP
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