The city has found a company to recycle clamshell plastic containers collected in blue carts since April, but a cache of plastics sitting in storage will have to be sent to a landfill, officials said Tuesday.

Changes to global recycling markets have meant limited options for recycling things like clamshell plastics. That meant the city was forced to put them in storage from September 2017 to April of this year and about 2,000 tonnes will be sent to a landfill this month.

"This is the first time we've had to landfill material due to market issues, and we are just as disappointed as many Calgarians will be about this,” said Sharon Howland, leader of program management with waste and recycling services.

“Our priority has always been to keep all recyclable materials out of the landfill. However, despite our best efforts to find a different solution, we now have to minimize the cost of storage of the backlog and focus our efforts on ensuring clamshells are recycled moving forward."

Clamshell plastics are the containers that things like pastries, berries and butter lettuce comes in.

It has cost the city about $330,000 to store the materials for the last two years and it will cost about $130,000 to send them to a landfill.

“The total cost works out to $1.40 per blue cart household for the storage and landfilling of this material over the entire two-year period,” the city said in a release.

“The City explored more than 50 different options, including recycling, alternative use and waste-to-energy for the stored clamshell plastic. Most of the clamshell material was considered unmarketable as it did not meet the requirements to allow the material to be turned into something new.”

Howland says the clamshell containers represent about one or two per cent of the annual blue cart tonnage.

In a release, Coun. Peter Demong said having an Extended Producer Responsibility program in the province, which would make producers responsible for products once they reach their end of life, would help stabilize recycling markets.

"As municipalities, we are just not as equipped to deal with fluctuating markets as producers are, and taxpayers should not have to bear the financial and operational risks that come with them,” he said.

“Producers need and want to be given responsibility for the post-consumer products and packages they sell.”

The city says currently 95 per cent of households are using their blue cart on a regular basis. The city has recycled more than 600 million kilograms of material over the last 10 years.