Study to look at health of uranium mine workers

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The Saskatchewan government is partnering with mining companies Cameco and Cogema and the Canadian Nuclear Safety Commission (CNSC) to conduct a study looking at the health of workers in the province's northern uranium mines.

The study actually includes two separate studies, one looking at the health of workers in uranium mines prior to 1975, and the other a feasibility study to determine if a similar study can be done of the people that have worked in uranium mines since 1975.

Rachel Lane is an epidemiologist with the CNSC, and is working to co-ordinate the study.

The study grew out of a recommendation, made in 1993 by a joint federal-provincial panel on uranium mining in northern Saskatchewan, that an ongoing epidemiological study be done of all Saskatchewan uranium miners, past present and future, Lane explained.

An epidemiological study looks at possible risk factors that could lead to a specific disease, and at how many people exposed to those risk factors actually are diagnosed with the disease. Those facts are then put together to try to determine the probable link between the risk factors and the disease.

"The over-arching objective is to estimate the risk of lung cancer from radon exposure within Saskatchewan uranium mines and to look at modifying effects on that relationship such as age of first exposure, time since last exposure, so all the details of that relationship. As well as for the modern miners study, to look at confounding effects of cigarette smoking, because cigarette smoking is the number one risk factor for lung cancer, and that is an important factor to look at when we're looking at lung cancer," Lane said.

A decision was made to split the study in two, with the first part being an update of an earlier study-the Eldorado cohort study, a health survey of approximately 20,000 miners working for Eldorado Nuclear Ltd., the federal Crown corporation that oversaw Canada's uranium mining interests from the 1940s, up until 1988, when Eldorado merged with the Saskatchewan Mining Corporation to form the Cameco Corporation.

"The original Eldorado study was conducted in the 1980s. And it consisted of all workers at Port Radium, which is in the Northwest Territories, Beaverlodge, which is a Saskatchewan uranium mine, and Port Hope, Ont. Port Hope is the radium and uranium processing plant . . . the mines in Port Radium and Beaverlodge would send down their products to Port Hope. So basically at that time, in the study, information was being collected on all of the miner's work histories, and their radiation exposures. And the mines were open at various times. Port Radium was, we're talking about the 1930s and 1940s, when these mines were originally opened."

The Eldorado survey collected information on the miner's work histories and radiation exposures, Lane said, explaining that the data on radiation exposure levels collected at the time the miner's were working came from measurements of radiation in the work area, and wouldn't have been as precise as information gathered today, when workers each carry a personal dosimeter that registers their exposure level.

The information collected in the Eldorado study was then linked to the Canadian mortality data base, which contains information on all causes of death of Canadians, and data was gathered on all cohort members who had died between 1950 and 1980.

"The study showed basically that there was an excess of lung cancer among uranium miners at Beaverlodge and among underground miners and surface workers at Port Radium. Now that makes sense because they're both uranium mines. But there was no unusual mortality among the radium and uranium workers at Port Hope," she said.

"So the update of the Eldorado study will basically take the Port Radium, the Beaverlodge and the Port Hope original group of employees, and instead of just doing a mortality linkage to 1980, we will extend that now to present time. So we basically have from 1950 to 2000 of mortaity follow up. And these last 20 years are important because the workers will naturally be having higher rates of mortality because they're aging. So we anticipate more deaths because of just sort of natural mortality patterns. In 20 years, additional mortality is very substantial. We're also going back and reviewing all of the worker's work histories. In the old days, all of this information was collected on paper. So we've gone back and reviewed them all and made corrections where there were problems. We have sorted out duplicate records and so on. And as a consequence of that, we're getting more information on the individual miners and we're getting better estimates of what their actual radiation exposures were. So that will also go into sort of improving the information in, and then when we link to the mortality data base, we'll be able, in our analysis, we will find out what their causes of death were, and we'll be able to estimate the risk of lung cancer from their radon exposures," she said.

"The second study looks at modern miners, so that's from 1975 probably until way into the future. Now, what we're doing now is a feasibility study, and it is underway. And the feasibility study will look at what the exact objectives we need to be looking at, whether to do a surveillance study, or to do a risk assessment study, or so on. So the people that we hired will be setting out what the best objectives are, study design, who will be included and excluded in the study, what exposures we are interested in. We're obviously interested in radon, radon progeny, gamma, and so on. Measurement of confounders-now the most important confounder, like I said, was smoking-and how are we going to capture that information among these men, and how are we going to follow up these men through time, because men will leave the mining company and move on to other jobs, and how do we collect information on them for finding out what's going to happen to them 40, 50 years down the line? S that's all being done now as part of a feasibility study. Once the feasibility study is finalized, we'll come back and look and see how to proceed with the modern miner study."

The results from studies such as these have a practical application for mineworkers everywhere, Lane explained.

"Let's go back to the original study. The information from this study, as well as studies conducted elsewhere around the world on uranium miners, all that information goes into the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Information on radiation research is compiled and reviewed and so on, and that information basically sort of sets, this is our current knowledge about radiation in the world.

"That information then impacts on what's called the ICRP, the International Committee on Radiation Protection. And that ICRP sets international standards. So from this information, we know what are safe levels of exposure, and ICRP sets international standards based on what is safe. The CNSC, we are a regulatory body, and we set Canadian regulatory standards based on ICRP. So it's all part of a circle. One study does not set the rule, but the accumulation of knowledge sets solid, scientific information in order to set standards and regulations to ensure the safety of, in this particular case, uranium miners," said Rachel Lane.

The estimated cost of completing the update of the Eldorado cohort study, and the feasibility study to determine if a study can be done of modern uranium workers is $180,000. The Saskatchewan government will cover a third of that cost, with industry covering another third, and the final third being paid by the CNSC. And, while that funding is to cover expenses for two years, the work being done will continue long past that time frame.

"The modern miner study, if it is shown to be feasible, will be a long way into the future. We'll be actually doing data collecting for many years, and then we'll be doing an analysis in the uture," Lane said.

Clarence Natomagan has a unique perspective on the uranium workers study. Natomagan is Cree, originally from Pinehouse, and before working for the CNSC as an environmental inspector, he spent 10 years working in the uranium mining industry-in the mines, in mill operations, and in radiation health and safety.

"Sometimes the environmental inspector title can be misleading, because I don't really work with the environment per se, like flora and fauna or anything like that," Natomagan says of his responsibilities with the safety commission. "I work mainly with the work environment, so it's more safety, radiation safety for the work environment."

As part of his job, Natomagan visits the mines, and has many opportunities to speak to the workers. He said the level of concern the workers express to him about radiation exposure is largely dependent on where they are working.

"I guess sometimes, the general feeling I get from just personal discussion amongst people that I'm close to, or people from back home that I meet throughout my travels at the uranium facilities, it depends sometimes where you work. Each of the facilities have different ore grades, different strengths of exposure, if you want to call it that. McArthur seems to be one of the places where the uranium ore grade is a lot higher than it has been historically for all the other facilities," he said.

"The people that actually work at McArthur, they have a lot more questions, or concerns if you want to call them that. But their curiosity is a little bit higher than it is working in Key Lake, previously. But now that Key Lake is also milling the ore from McArthur, which is a higher grade ore, the concerns are there too. People always ask questions in regard to radiation safety, 'How much is too much?' and 'What is safe for me?' And normally I like using analogies, such as people who chose to smoke. You use analogies or comparisons like that. Flying from here to one of the Atlantic provinc