A CBC investigation into Canada's two largest coffee companies has led to more revelations about poor environmental practices at Starbucks and Tim Hortons.

The stories come on the heels of a CBC Marketplace investigation, revealing how paper cups that customers tossed into store recycling bins at Toronto Starbucks and Tim Hortons were actually being thrown into the garbage, not recycled at all.

After the story aired, Starbucks issued a notice to be posted in stores for customers to read.

It said, "Upon hearing of some stores that had not disposed of recyclable material properly, we immediately conducted a review of all our stores across the country, and are taking steps to ensure and confirm that all our stores are delivering on our recycling commitment."

A notice posted in Starbucks outlets says the company regrets 'disappointing any customers or partners.' (CBC) The notice also says the company regrets "disappointing any customers or partners."

But now, current and former employees at both Starbucks and Tim Hortons tell CBC that they, too, have witnessed environmentally unfriendly practices for years.

A current Vancouver-area Starbucks manager describes overflowing recycling dumpsters behind numerous Starbucks stores he manages today — so full, he says, paper cups and other recyclables have to be thrown in the garbage.

But he says when he and other store managers asked a district manager and an area facilities service manager a year ago what private company was supposed to be picking up the recycling, they were told to "move on to something more important."

The manager says he is "frustrated" that Starbucks "pretends to be much more environmentally friendly than it is."

3 holes, one garbage bag

Several Toronto Starbucks employees describe how some in-store recycling bins had three holes for separating recyclables, but only one bag, so everything got mixed up together and was then thrown in the garbage dumpster.

"I was instructed that they do get thrown out, because we actually do not recycle at that facility," said someone who stopped working at that Starbucks in May.

An employee who worked at three Toronto area Starbucks for two years but left in October 2014 for full-time work elsewhere wrote to CBC about the plastic containers used for flavoured drinks.

"Every syrup container and frap base container is thrown IN THE GARBAGE every day… We threw out garbage bag after garbage bag every night."

The employee added, "Not to mention the compost that could be made of the coffee grounds that were constantly thrown out."

Workers at Tim Hortons shared other environmental concerns.

An employee currently working at Tim Hortons in Brechin, Ont., says people who think they are avoiding paper waste by bringing portable coffee mugs are being "duped."

Starbucks and Tim Hortons coffee cups ended up in the garbage despite the companies' recycling claims. (Associated Press) In an email, she writes, "We are encouraged to make their coffee in a paper cup and pour it in the travel mug... to make sure we are not giving more coffee than purchased."

She says, "The paper cup then goes into the garbage with no environmental savings."

Several other Tim Hortons employees have shared the same concerns. And on Nov. 5 CBC witnessed this at a Tim Hortons right below the CBC's Canadian Broadcasting Centre in Toronto.

Also in Toronto, many of the Tim Hortons stores visited by CBC were using black garbage bags in their recycling containers instead of clear ones designated for recycling in Toronto and many other municipalities.

A former Tim Hortons worker emailed to say black garbage bags were also used for recycling at the stores she worked in three years ago in Saint John, N.B., and Fredericton. "When the garbage is changed, everything is put in black garbage bags & thrown in the ONLY garbage dumpster they have," she writes.

In-store recycling bins

Starbucks and Tim Hortons have championed various environmental programs, saying in annual reports that environmental leadership is important. A key program by both companies was introducing in-store recycling bins more than five years ago.

Today, Starbucks says those blue recycling bins are in about half their stores across Canada. Tim Hortons says the recycling bins are in almost a quarter of their stores. As of June 2013 there were 3,400 Tim Hortons stores in Canada. As of 2014 Starbucks had 1,400 Canadian outlets.

Neither coffee giant agreed to be interviewed for the Marketplace investigation, which stirred up a storm of controversy on social media.

<a href="https://twitter.com/cbcErica">@cbcErica</a> - thank you for exposing the truth behind <a href="https://twitter.com/StarbucksCanada">@StarbucksCanada</a> & <a href="https://twitter.com/TimHortons">@TimHortons</a> so called "recycling" program. Greenwashing @ it's finest —@PurpleGrape07 <a href="https://twitter.com/cbcmarketplace">@cbcmarketplace</a> watched episode on coffee cups recycling and was VERY disappointed in both Tim's & Starbucks! Shame on you! —@daniesgurls5 Just watched <a href="https://twitter.com/cbcmarketplace">@cbcmarketplace</a> I will be passing on <a href="https://twitter.com/Starbucks">@Starbucks</a> & <a href="https://twitter.com/TimHortons">@TimHortons</a> coffee until they quit lying abt their recycling program. —@SouWestActivist <a href="https://twitter.com/hashtag/TimHortons?src=hash">#TimHortons</a> & <a href="https://twitter.com/hashtag/Starbucks?src=hash">#Starbucks</a> Thx 4 the lip service on ur recycling program. My lips won't b touching ur products any time soon <a href="https://twitter.com/cbcmarketplace">@cbcmarketplace</a> —@YChevtchouk <a href="https://twitter.com/cbcErica">@cbcErica</a> - thank you for exposing the truth behind <a href="https://twitter.com/StarbucksCanada">@StarbucksCanada</a> & <a href="https://twitter.com/TimHortons">@TimHortons</a> so called "recycling" program. Greenwashing @ it's finest —@PurpleGrape07

The investigation featured two Marketplace employees outfitting paper coffee cups with tracking sensors, and then dropping them in recycling bins inside Toronto Starbucks and Tim Hortons stores. Later, the employees returned and found half of their 28 cups were in the garbage, not recycling. The other 14 cups could not be located.

A Tim Hortons sign stands near Walker Road and Wyandotte Street East in Windsor, Ont. (Geoff Nixon/CBC) Adria Vasil, the bestselling author of the Ecoholic book series and green columnist for Toronto's NOW magazine, says she was "outraged" by the results of the investigation.

"Clearly, these companies know the benefit of good green PR. They don't want customers to feel guilty about throwing out all those cups, and they've leveraged goodwill out of those green campaigns. And then to turn around and do nothing about implementing them properly, and making sure that it's not just a bunch of hot air is maddening."

Vasil worries that a demonstrated lack of corporate action can wear out the public's goodwill when it comes to supporting environmental programs.

"It makes you wonder about all their ... green sustainability programming. How much is authentic, and how much is just lip service? I think we could expect this even a decade ago, but today I am shocked to see such big chains acting with so little regard to the environment."

Customers complain

Several people who viewed the Marketplace investigation wrote to Starbucks to express their disappointment and shared their correspondence with CBC.

In Ottawa, realtor Tim Dillon told the company, "Not recycling yet you say you do is just deceptive. I now wunder (sic) are your other...programs real????? I will take my money elsewhere. I spend about $60 per week at your stores."

CBC shared the workers' concerns with Starbucks and Tim Hortons, and requested interviews with both companies. Both companies declined.

In an email that did not address the workers' concerns raised, Starbucks said the company is "committed to recycling and reducing the impact of waste generated in our stores."

Tim Hortons did not address the issues raised by workers, either, but in an email said the company was proud of its recycling and waste initiatives and they "know there is more work to do."

This story is based on an investigation by Tiffany Foxcroft.