Some of them were in those plastic (polymer) sleeves while others were in the standard paper. 90% of my city was without power for close to three weeks. No AC with 100% humidity and actual temperatures in the upper 90's can wreck havoc to the inside of a home.
However, we also had some storm water blow in thru an attic vent, then slowly dripped down the inside the wall of my bedroom. The sheet rock became wet and moldy and it spread to a few LP's I had leaning against that wall.
Robin Hood is more real than Jesus - Rob Instigator