Sold and marketed as environmentally friendly, compostable food packaging has been exploding in popularity in Australia.
The plant-based fibre and bioplastic packaging can now be found at thousands of cafes and takeaway shops, as well as supermarkets for use at home.
Many consumers are happy to swap single-use plastic for compostable packaging.
But is it really any better than the plastic it has replaced?
What is compostable packaging?
It is food packaging designed to break down into soil when put in a home composting bin, or industrial Food Organics and Garden Organics (FOGO) plant — the place your green bins are emptied at.
It's usually made from plants such as sugarcane, which are turned into paper-like materials or bioplastics.
Sometimes the packaging is both — a paper-like material, which is then lined with bioplastics to reduce liquids seeping through.
Is it regulated?
There is a voluntary certification system through the Australian Bioplastics Association, but because the industry isn't regulated, all sorts of materials are being called "compostable".
While you might see some confusing labels put on packaging, there are just two labels that are proof a product meets Australian standards for composting.
But seeing that label doesn't mean your packaging will actually be composted.
Only South Australia has a statewide system allowing compostable packaging to be put in green FOGO bins.
So, if you're disposing of the packaging from your home or anywhere else across most of the country, it's likely not going to be composted.
Few public spaces have FOGO bins at all and most that do aren't allowed to accept compostable packaging.
So, in the vast majority of places, it needs to go in red bins, and thus ends up in landfill.
Is compostable material better for the environment in landfill?
That isn't clear yet.
When organic material such as plant-based packaging breaks down in landfill, it creates emissions of the very powerful greenhouse gas, methane.
Landfill is a huge emitter in Australia, contributing about 30 per cent of Australia's methane emissions.
So while some compostable packaging might not last practically forever in landfill the way plastic does, the faster degradation in landfill comes with a bigger hit to climate change too.
There are other downsides too.
Tony Chappel, the CEO of New South Wales's Environment Protection Agency, says the more inert — or chemically stable — a material is, the safer it is in landfill. Compostable material is not inert.
If the material breaks down, then there is a higher chance potentially dangerous chemicals will leak into the environment.
What chemicals are there in compostable packaging?
One of the thousands of problematic substances found in a lot of compostable packaging is PFAS, known as a "forever chemical".
PFAS — or "per- and polyfluoroalkyl substances" — are a group of chemicals used in products ranging from cookware and clothing to cosmetics and food packaging.
They are popular because they repel water and oil, and help insulate heat.
Unfortunately, their other property is that they don't break down in the environment.
And according to the Australian government, they could be harmful to human health, with potential risks to our livers, guts and thyroids.
A 2021 study by the Australian Packaging Covenant, found nearly 30 per cent of compostable packaging had high levels of PFAS.
And the general consensus is we don't want any of that in the compost used to grow our food.
What are we doing about that?
Compostable packaging has now been banned from green bins in a number of states.
Why?
Those chemicals, for one — but also because of the other plastic packaging that wrongfully ends up in compost bins.
The messaging around what is and isn't allowed is confusing.
Despite "compostable" products meeting the Australian standard for certification, a CSIRO study found their presence in soil meant earthworms and roots did not grow normally.
BioPak, Australia's biggest producer of compostable packaging, says it has replaced PFAS in all of its products.
Co-founder and chief executive Gary Smith says the company worked hard to ensure it was not replaced with something worse.
The packaging industry says PFAS will be gone from its products this year, and the federal government says it will regulate them out by 2025.
So, should we be using compostable packaging at all?
It depends who you ask.
Gayle Sloan is head of the Waste Management and Resource Recovery Association of Australia, which represents all the industries that deal with waste and recycling.
Ms Sloan says compostable packaging could be useful if we had a system set up around it to ensure it is safe and actually ends up in compost.
She says manufacturers should take responsibility for making sure that happens, but for now, compostable packaging isn't something we should be encouraging more of.
"It's a good idea in theory, but in practice, we don't have the system for them at scale," she says.
BioPak's Gary Smith says it is a waste to send to landfill, but even there, it is better than single-use plastics.
He says the answer is regulation to make sure compostable packaging is safe and banning any other type of packaging so there is no more confusion or greenwashing.
Mr Smith says composting of BioPak's packaging in South Australia is working well, and could be a model for what should happen throughout the country.
Could the bans lift soon?
Mr Chappel says the NSW EPA is open to reconsidering the place of compostables in green bins — but probably not within the next five years.
He says the organisation is leading the way nationally with its testing of the materials and its ban.
"I know a number of states are doing significantly more testing as a result [of our work] and I understand some of those results also find similar outcomes to what we've observed," he says.
Environment ministers across the nation have agreed to a uniform approach — whether that will be a win for compostable packaging or not is yet to be seen.
Federal environment minister Tanya Plibersek says where we do use single-use items, they need to have the lowest possible impact on the environment.
"Compostable packaging is part of that story," she says.
"I think we should be reducing the amount of waste we create in the first place."