Sprint and AT&T will let customers exchange their replacement Galaxy Note 7 devices at a retail store for any other smartphone available following concerns that the new devices may still not be safe to use. Sprint told Recode that its offer will last through the current “investigation window,” while AT&T confirmed the exchange policy with TechnoBuffalo.

Sprint added that the carrier is  “working collaboratively with Samsung to better understand the most recent concerns regarding replacement Samsung Galaxy Note 7 smartphones.” Verizon and T-Mobile have yet to confirm similar return policies.

UPDATE: A T-Mobile spokesperson has reached out with the following statement: 

Customers with an original Note 7 can return them anytime for a replacement Note 7 or a full refund that they can use as they want and get any device we carry. Customers with a replacement Note 7 or a new Note 7 purchased since we resumed sales on Wednesday, October 5 can get a full refund within 14 days and get any other device we carry.

We still don’t know whether the new Galaxy Note 7 units are actually dangerous, but there’s reason to be concerned. Earlier this week The Verge reported that one of the replacement devices caught fire on a plane and forced an evacuation shortly before takeoff, offering a photo of the smartphone’s packaging as evidence.

Samsung is still looking into the incident to determine if a new Galaxy Note 7 was to blame. The U.S. Consumer Product Safety Commission is also investigating whether the replacement units are safe. However, if there is a serious issue with the device, it could be months before another recall is officially announced.

In the meantime, more carriers should follow the lead set by AT&T and Sprint.