CNN  —  Concern is rising in Gulf Arab states about the possibility of environmental contamination or reprisal attacks if Israel or the United States strikes Iran’s nuclear facilities just across the Persian Gulf. In Oman, users on messaging apps circulated advice on what to do in the event of a nuclear incident. Residents are instructed to “enter a closed and secure indoor space (preferably windowless), seal all windows and doors tightly, turn off air conditioning and ventilation systems” if