That’s ok. US troops are not allowed to use CS at all.
I've had US troops use CS on me lots of times.
The worst was while in the back of a deuce & a half with the cover on, but open in the rear. Two CS grenades were thrown into that opening from a passing OPFOR jeep. It was only a FTX, but the CS was real. I saw them coming and managed to get masked quickly so I only cried a little. Two squads were in the truck, most got dosed much worse than me.