Apple prides itself on being as “green” as it can and, indeed, has plenty of eco-focused initiatives under way. In fact, its new campus will take advantage of clean energy. There are some concerns that its most recent product launch, Apple AirPods, aren’t easily recyclable, however.

Reuters cited iFixit on Tuesday, which said that the small batteries attached inside the AirPods will make them difficult to dispose of in mass quantities. While supply of the buds is currently extremely limited, iFixit head Kyle Wiens suspects they may one day be as popular as Apple’s included earbuds. “They’re basically saying this is the future of headphones,” said Wiens, who told Reuters that Apple has probably sold about 31 million pounds of its traditional headsets.

In other words, you may look the AirPods and shrug off that they could possibly have any tangible environmental impact, especially given how small they are. But, over time, as millions and millions (or even more than 1 billion, as Wiens pegs the number of wired buds sold), are put into circulation, then recycling may become a concern.

AirPod batteries to blame

“Recyclers can shred wired headphones and send them to a smelter that will melt them down for the copper inside,” Reuters explained. The new AirPods pack three batteries inside, however, which means that users can’t just dump them into a recycling machine and, instead, they’ll need to either be put out with other tech waste or sent back to Apple, while told Reuters it will take care of recycling.

Keep in mind that the AirPods aren’t some sort of anomaly here; this applies to all gadgets with lithium ion batteries, including similar-style headphones from competitors such as Samsung. If you can’t just pop the battery out, then recycling isn’t as easy.