[alienchow]

I'm not sure either. It's not an air tight bomb shelter and it's used like an average storeroom, storing stuff like winter jackets, suitcases and paint. I do use small amounts of Calcium Chloride based dessicants to keep the room dry.

[mixologic]

Have you checked for Radon?

[ajross]

Radon is a noble gas and chemically inert. It's radioactive, which is why it's a toxicity worry. But there was enough radiation in that basement to mechanically damage plastic in three years, OP would be long since dead.

[lima]

Radon and its progenitors won't produce nearly enough radiation to damage plastics like that at naturally occurring levels.

[mzhaase]

Water based or solvent based paint?

[alienchow]

Should be solvent based.

[chneu]

If it's underground at all, check for radon.

[CamperBob2]

Radon is a noble gas. It's not going to affect fiber or wiring... but yes, if you're going to spend much time down there, definitely a good idea to check for it.