Reusable eco-bags, often touted as greener alternatives to plastic bags, may not be that environmentally friendly after all.
Experts have warned that their prevalence may soon be counterproductive to green aims.
"If a reusable bag is used just once and then thrown away, then... it may not be the more environmentally friendly option," said environmental group World Wide Fund for Nature Singapore's chief executive Elaine Tan.
The problem, ironically, is the bags' popularity. When there are so many lying around, they are rarely reused sufficiently.
Nurse Magdeline Koh, 54, has close to 30 such bags. "Even though I try to re-use these bags, it's impossible," she said.
For the bags to be truly environmentally friendly, they must be used many times.
For a standard reusable bag to have a lower carbon footprint than a high-density polyethylene plastic bag, it must be re-used at least 11 times, according to a 2011 study by Britain's Environment Agency.
It gets worse for cotton reusable bags. They should be re-used at least 131 times.
Yet, consumers keep buying and receiving more such bags.
Supermarket chain NTUC FairPrice, for instance, said it has seen a more than 20 per cent increase in the number of reusable bags sold last year, compared to 2013.
Instead of paper bags, many companies also prefer to issue reusables now.
Avid runner Darren Ang, 32, said organisers of fitness events, for example, are giving out more such bags.
"They used to give out sling bags, but switched to reusable bags three to four years ago," he said.
The health, safety and environment head at an oil and gas company has more than 30 such bags, all from corporate events.
The National Environment Agency said it does not regulate the distribution of reusable bags.
To make things worse, the various green agencies in Singapore have differing views on the best way to discard extra bags.
While one said it could be grouped with your recycled trash, another said it should be thrown away with regular rubbish.
But the upside is that the abundance of reusable bags has slowed the growth in the number of plastic bags.
Singapore uses about three billion plastic bags each year, a figure which has remained constant over the past five years, said Singapore Environment Council's resident environmental engineer Kavickumar Muruganathan.
FairPrice said it helped save more than eight million plastic bags in 2013, up from 7.2 million in 2012.
Its Green Rewards Scheme, which gives customers who take along their own bags a 10-cent rebate for a minimum purchase of $10, gave out $410,000 in rebates in 2013, up from $360,000 the year before.
For Mr Ang, who keeps four to five reusable bags in his car for weekly grocery trips, using them helps minimise the negative environmental impact of plastic bags.
"Seeing sea creatures entangled in plastic bags and fishing lines during a coastal clean-up in 2008 really (affected) me," he said.
"By carrying reusable bags, I hope to change the misconception that such bags are only for 'aunties'."