Last year, it cost nearly $300,000 to rent semi-trailers to house the hard-to-reprocess material, a practice dating back to September 2017.
About 1,600 tonnes of the plastics now fill 100 storage units, said a city official.
That could bring the total spent to about $500,000, and the volume of plastics and the space required to store them at the Shepard Landfill site is growing at the pace of two to three trailer units a month.
Processors generally spurn the packaging due to contamination from labelling and adhesives.
Ward 1 Coun. Ward Sutherland said he was surprised to hear about the growing number of trailers packed with the bailed plastic and the cost, adding the city should consider cutting its losses.
“I question the value of storing versus executing other options, such as burning, landfill,” he wrote in a text message.
“I am disappointed this was not brought to council and the chair’s attention. I will address this through committee immediately.”
The city has had success in finding out-of-province processors to take most of its plastics, glass and paper recyclables after China stopped accepting them in late 2017.
Clamshell packaging — used to hold baked goods and produce — makes up one to two per cent of all recyclables collected by the city, said Sharon Howland, leader of program management for the city’s waste and recycling services.