white liquid/paint/foam dropped on the madleen from a drone

just been watching a telegram livestream from someone on board the madleen. as you may have heard there was a false alarm (likely a false flag to test their reaction) about half an hour ago. but in the last 5 minutes: they reported a drone flying overhead, the drone dropped this white foam/liquid/paint? all over the ship. what is it???? they all put on masks, complained of a terrible smell and burning eyes. can anyone guess what it may have been? the stream just cut off straight after this in the middle of a sentence.