Those should be fine since they don't have teflon and teflon-related materials: they are non-BPA plastics with silicon seals. Just don't microwave plastic (There are a lot of "ifs" and "buts" around that, but it is better just to not microwave plastic and be safe.) Granted, you are still throwing away plastic once the snaps break. They also make similar types with bamboo lids and a silicone seal.
(Hopefully if I'm wrong someone will shout me down with the correct answer :)
(Hopefully if I'm wrong someone will shout me down with the correct answer :)