Samsung's busted Galaxy Note7 phone may have become a punchline, but 4.3 million dumped devices is no joke to the environment, Greenpeace warns.

Now that the Korean phone giant has recalled millions of the devices after a recent global fiasco in which multiple devices were found to be fire hazards, it's important to dispose of them in a safe way, the environmental group says.

If the phones end up in a landfill or get burned, they'll release toxic chemicals into the air. Metals in the phones such as tungsten, cobalt, silver and gold are also worth recycling.

Jude Lee, a senior IT campaigner for Greenpeace East Asia, told Mashablethat the proper way to dispose of a phone is to recover reusable minerals and metals from the handsets and ensure that plastics are properly recycled.

Samsung could also come up with a recycling programme for the devices to get repurposed into future handsets, she suggested.

Sadly, Lee could not single out a tech company that's doing things right.

And while some retailers in the U.S. (like as Best Buy and Target) have recycling kiosks for old gadgets, Lee pointed out that oftentimes the final resting place for many phones is on a disassembly line in small companies where phones are dismantled by hand, exposing workers to toxic substances.

According to the United Nations Environment Programme (UNEP), recycling markets in developing countries like China, India, Pakistan, Vietnam and the Philippines handle up to 80 percent of electronic waste. There, workers shred and burn IT products in a backyard environment, creating emissions that are harmful to humans and the environment.

Environmental Science and Technologypoints to the residents in the Chinese city of Guiyu, where lots of e-waste is recycled. The majority of the children in Guiyu show signs of respiratory issues, it said.

Samsung said in response to a query we sent: “We recognize the concerns around the discontinuation of the Galaxy Note7 and are currently reviewing possible options that can minimize the environmental impact of the recall in full compliance with relevant local environmental regulations.”