OTTAWA -- A Federal Court decision allowing a lawsuit over pesticides blamed for decimating bee populations could affect dozens of common agricultural chemicals, environmentalists say.

"This case illustrates a problem with how (Health Canada) approaches pesticide regulation and we're hoping the court agrees with us that process needs to be tightened up," said Lisa Gue of the David Suzuki Foundation, one of four groups behind the lawsuit.

The claim asks the court to revoke Health Canada permits for two of the country's most commonly used pesticides -- so-called neonic insecticides. This week, Federal Court rejected an appeal from Health Canada and several chemical companies to have the lawsuit dismissed.

Research suggests a link between neonics and plummeting populations of bees, which are crucial for the pollination of about one-third of human food crops.

The Canadian Honey Council reported that in 2013-14 Canadian beekeepers lost an average of about 25 per cent of their colonies. Ontario's losses were 58 per cent.

The University of Guelph's Honeybee Research Centre blames a combination of disease, parasites, pesticides and habitat destruction. Last fall, scientists from the International Union for Conservation of Nature met in Ottawa to say neonics are not only fatal to bees, but also to frogs, birds, fish and earthworms.

The lawsuit claims Health Canada's Pest Management Regulatory Agency has, for more than a decade, permitted the chemicals without having adequate data on their effects. It alleges the agency asks manufacturers for more information, then repeatedly issues conditional permits despite that information never arriving.

"Health Canada has been keeping these registrations active for these pesticides for more than a decade now without properly assessing their risks," Gue said. "We are challenging the government's practice of issuing conditional registrations."

There are 36 other agricultural chemicals that also have conditional permits.

Health Canada has argued the lawsuit isn't needed. A review of neonics is underway, it says, and conditional permits are no longer issued.

A department spokesman said updated measures to protect pollinators are expected late this year, although measures to protect aquatic life aren't planned until 2020.

Health Canada has proposed new restrictions that include banning neonics from being sprayed on orchards and turf sites and reducing their use on vegetables. It has found one neonic -- not included in the lawsuit -- should be banned almost entirely because it has been found to kill aquatic insects that are a source of food for fish and birds.

Gue praised those efforts and the end of conditional permits. But, she said, that's not enough.

"They are tinkering with requirements for use. The government has not proposed to actually end the registration of the active ingredients that are the subject of our lawsuit."

She pointed out the review and phase-in process will take years and neonics will remain in use. As well, conditional permitting remains on the books, even if the government has chosen not to use it.

"That regulatory mechanism remains available and we are concerned it could be used in the future."

Europe has imposed a moratorium on neonics. The U.S. has banned new uses for them.

The Conference Board of Canada, in a 2014 report supported by the Grain Farmers of Ontario and CropLife Canada, estimated that a neonics ban would cost Ontario farmers $630 million a year.

European scientists have said crop yields haven't suffered since the neonic clampdown there.

By Bob Weber in Edmonton