# Styrofoam

**URL:** <https://boards.straightdope.com/t/styrofoam/75795>\
**Category:** Factual Questions\
**Created:** [August 11, 2001, 1:12pm UTC](https://boards.straightdope.com/t/styrofoam/75795 "2001-08-11T13:12:57Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Boss](https://avatars.discourse-cdn.com/v4/letter/b/c77e96/32.png) [@Boss](https://boards.straightdope.com/u/Boss)\
**Post date:** [August 11, 2001, 1:12pm UTC](https://boards.straightdope.com/t/styrofoam/75795/1 "2001-08-11T13:12:57Z")

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The place where I work has a dining room where we get large styrofoam cups to drink from. I usually drink ice water and have noticed something unusual. After filling a cup with ice and water and letting it sit for awhile, it sweats. This part I understand, as it is the difference in temp between the cup and the room air. However what the cup sweats is blue, like Listerine. Why? Is this a chemical residue from the styrofoam? Is it safe? Am I drinking this?

Thanks.

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**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\
**Post date:** [August 11, 2001, 1:34pm UTC](https://boards.straightdope.com/t/styrofoam/75795/2 "2001-08-11T13:34:40Z")

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Interesting. Is the liquid actually blue, or does it merely _look_ blue? I.e. if you wipe it off with a kleenex, does it look blue on the kleenex?