While the Google Fitbit Air‘s launch was anything but ideal, particularly for some customers, it has served as a decent alternative to Whoop’s offering. As with most new hardware, customers aren’t always aware of what may harm their devices, and one user has just learned this the hard way.

Detailing the ordeal on Reddit, user le_cs claims to have used bug spray on their shirt ahead of a hike, which eventually rubbed off onto their Fitbit Air, causing the plastic on the fitness tracker to break down (via Phandroid).

As a user in the comments rightly notes, the main culprit here is DEET (N,N-diethyl-meta-toluamide), typically used in insect repellents. DEET is known to impact certain materials, including plastic, which plainly explains what went wrong here.

The affected user claims Google deemed this as “environmental” damage, thereby rejecting any warranty-related claims.

While the discoloration of the plastic may not be a sufficient reason to seek a replacement for your Fitbit Air, the user states the sensors are “too clouded,” meaning they won’t get accurate readings from the device. Moreover, the individual claims their wife’s Fitbit Air has met the same fate.

Although the Fitbit Product Care page specifically mentions avoiding insect repellent sprays, the Fitbit Air Safety & Regulatory Guide and the support page make no mention of it. Still, the fact that products that contain DEET can affect plastic is well known.

In fact, a few Fitbit Air owners have already voiced this specific concern on Reddit, serving as a warning to fellow owners to avoid DEET-containing products before their activities.

While users may try to avoid products with DEET when using the Fitbit Air, there’s no guarantee these products won’t affect the fitness tracker. The Fitbit support page doesn’t mention DEET specifically, but asks users to “avoid any direct contact with sunscreen or insect repellent sprays.”

So if you’ve recently bought yourself a Fitbit Air, all you can do is avoid exposing it to sunscreen or other commonly available bug sprays.