"(Environmental groups) have made numerous efforts over the past 10 months to have the government comply with its legal duty to subject these pesticides to special reviews," said Lara Tessaro of Ecojustice, which is representing the David Suzuki Foundation and Equiterre.
"The government has now outright refused to do that for three pesticides and is delaying its decision for 26 more."
But an industry spokesman said those chemicals have been recently and thoroughly reviewed and are safe when used properly.
The chemicals include chlorthal-dimethyl, a possible carcinogen and herbicide most commonly used on weeds in vegetable operations; trifluralin, a popular herbicide on the Prairies that's highly toxic to fish; and trichlorfon, an insecticide approved for woodlots, Christmas tree plantations and cattle that has been linked to human nerve damage.
The chemicals are found in about 700 commercially available products, said Elaine MacDonald, an Ecojustice scientist.
All three have been banned in Europe for at least six years.
"There's no exaggeration to say these are risky, dangerous chemicals," MacDonald said.
The lawsuits argue that under federal legislation, Health Canada is obliged to review any pesticide banned by any country belonging to the Organization for Economic Co-operation and Development.
"The purpose of a special review is to ensure that Canadians have a right to participate in decisions about whether those pesticides should stay on the market here," Tessaro said. "There would be an automatic right for environmental groups and other Canadians to give their views."
But over the summer, Health Canada's Pest Management Regulatory Agency told the environmentalists it would not review the three chemicals. It also said it would delay action by continuing to study 26 other chemical pesticides that have been banned in Europe.
The agency has told Ecojustice it needs to consider the reasons for the European ban.
"In our view, that's what the review is supposed to do," Tessoro said. "They're substituting a secret, internal review for a public one."
Health Canada reviewed chlorthal-dimethyl in 2008, before the European ban.
The agency found its risks were acceptable, even at levels exceeding those that prompted the ban. The Canadian review didn't include water monitoring data, although the chemical has been found in ground and surface water.
Quebec has banned that chemical for lawns since 2003.
Pierre Patelle, spokesman for pesticide industry association Crop Life Canada, said the other two chemicals have also been reviewed within the last five years.
"As part of that process, Health Canada looks at all the available data around the world on the active ingredient. Those products were evaluated and both were found to have acceptable risks."
"These groups — the answers they got were not what they wanted and now they're choosing a costly legal avenue as opposed to working with the system that's there," Patelle said.
That position is echoed in Health Canada letters to Ecojustice.
"The very aspects of concern identified in the OECD decision were already examined in the 2008 ... re-evaluation," said the letter concerning chlorthal-dimethyl.
Health Canada spokesman Sean Upton said officials are reviewing the applications and will respond within the time frame set by the court.
Ecojustice has filed four lawsuits, one for each of the refused chemicals and one for the 26 delayed chemicals.
Some of the delayed chemicals have not been allowed in Europe for nearly a decade. They include atrazine, an endocrine disruptor linked to human reproductive problems.
Patelle said some of the chemicals on that list were deregistered in Europe for business or other reasons that have nothing to do with safety.
MacDonald said the list was carefully reviewed to include only pesticides that involved safety concerns.