This problem came up this morning. I've passaged these 293T that I've received from somebody else four times and the last split was last night. This morning I found all my cells dead and I could smell something from my incubator. I could also smell it from the plates I split yesterday and it doesn't smell like bacteria or yeast. It was sharp, and it produces a reaction almost like what you would say about bleach. I think it smells like old DMEM or RPMI media but ten times stronger. The cells from the passage before were fine as far as I could tell, but I can also smell it from the media I used to culture my cells. I threw all the dead cells away but was wondering where it may be coming from and what might be the source. What contaminations may cause the media to smell?
Thanks for your help.