Canada's official environmental watchdog on Tuesday expressed concern that authorities were allowing the long-term use of pesticides linked to bee deaths despite not having enough information about the products.
The federal health ministry's agency responsible for pesticide regulation can grant a five-year provisional license to some products to give manufacturers time to provide more information.
Environment Commissioner Julie Gelfand said nine products had been remained conditionally registered for more than a decade, even though the agency had not gathered the data it required. Eight of the nine belong to the neonicotinoids class, which many bee keepers blame for devastating their hives.
"These products continue to be used extensively in Canada despite widespread concern they may pose a threat to bees, other pollinators and broader ecosystems," she said.
Pesticide use is a sensitive issue in Canada, where in July 2015 the province of Ontario became the first government in North America to curb use of seed treated with neonicotinoids, which are used to kill insects that harm crops.
Gelfand said the prolonged use of products with conditional registrations means "users may come to depend on a product that is ultimately shown to be unsafe."
In some cases, firms had not provided the required data for neonicotinoid pesticides. Even so, the agency continued to allow the products to be conditionally registered.
In a written response, the agency said it would gather the information more quickly in the cases of products which had been granted conditional registrations. The agency said last week it would stop issuing conditional registrations on June 1.
Earlier this month, the agency said available science suggested multiple factors could be responsible for bee deaths, including loss of habitat and food sources, diseases, viruses and pests, and pesticide exposure.
Separately, the agency concluded there was no risk to bees from the insecticide imidacloprid when it was used to coat seeds. But it found bees could be endangered when the pesticide was used to treat soils or applied to plants.
The U.S. Environmental Protection Agency said this month that its own preliminary risk assessment of imidacloprid found that chemical residues of more than 25 parts per billion would likely harm bees and their hives and result in the bees producing less honey.
Gelfand also found the agency had moved slowly to remove dangerous pesticides. It took the agency up to 11 years to remove some products deemed harmful.