A line of water bottles that had become a symbol of environmental responsibility has been removed from the shelves of Canada's leading outdoor gear retailer over concerns about a chemical used in its manufacture.

The Mountain Equipment Corp, which is based in Vancouver, British Columbia, removed the bottles, sold under the brand name Nalgene, and other polycarbonate containers from its 11 large-scale stores on Wednesday. The retailer said that it would not restock the bottles, which are made by Nalge Nunc International in Rochester, a unit of Thermo Fisher Scientific, until Health Canada completed a review of bisphenol-A, or B. P. A., a chemical used to make hard, transparent plastics as well as liners for food cans. "We've been following the B. P. A. issue for at least three years," said Tim Southam, a spokesman for Mountain Equipment. "The decision we've taken this week does not mean that polycarbonate products will never return to our stores. We're just seeking some certainty about this chemical."

Church and environmental groups in Canada have mounted campaigns against bottled water because of concerns about the huge amount of plastic used in containers. As a result, the reusable Nalgene bottles have become ubiquitous on college campuses and elsewhere.

Polycarbonate plastic, which can only be produced by using B. P. A., creates bottles that are transparent and almost as hard as glass, but particularly shatter-resistant. Recently, however, the use of B. P. A. -based plastics in food containers has been questioned in Canada by Environmental Defence, a Toronto-based group.

Environmentalists in the United States are also raising concerns about the chemical. Last year, San Francisco's board of governors passed a local law banning the use of the chemical in children's products. B. P. A. was removed from the ordinance before it went into effect, however, after an industry lawsuit. Critics point to studies dating back to 1936 showing that the chemical can disrupt the hormonal system.

While there is little dispute about that, the plastics industry, supported by several studies from government agencies in Japan, North America and Europe, contends that polycarbonate bottles contain very little of the chemical and release only insignificant amounts of B. P. A. into the bodies of users. "Rarely has a chemical been the subject of such intense scientific testing and scrutiny, and still, important agencies across the globe agree that there is no danger posed to humans from polycarbonate bottles," Tom Cummins, the director of research and development at Nalge Nunc, said in a statement.

Rick Smith, the executive director of Environmental Defence, said that a paper published by 38 scientists after a government-sponsored conference in the United States found that the lack of research on the effects of B. P. A. on humans was a concern that required further investigation. Steven G. Hentges, the executive director of the American Chemistry Council's polycarbonate group, takes issue with that report's worries and points to a separate expert panel report published by the United States Department of Health and Human Services last month. In its 396-page report, which looked only at the impact of B. P. A. on reproduction, the panel said it had "negligible concern" about the chemical's effect on adult reproductive systems but raised some concerns about its impact on children and pregnant women.