All of the smoke detectors in my buildings have sealed battery compartments in them. That means that you cannot replace the batteries or remove them without tearing the smoke detector apart and destroying it. I use smoke detectors with sealed batteries for your safety. Tenants often remove the batteries from their smoke detectors, and that is dangerous. What typically happens is this – a smoke detector goes off while someone is cooking, a tenant removes the batteries from the smoke detector but never puts the batteries back in. This has led to many, many deaths, including a few here in Berkeley. If you have a smoke detector that is not working properly or not working at all, contact me, and I will replace it immediately. Do not try to open the smoke detector or throw it in the trash. Smoke detectors are considered toxic waste, and you can be fined for putting one in your garbage can.