It was a calm Sunday in 2017 on the southern coast of England when people strolling along the shore were suddenly engulfed in a strange chemical cloud. More than 130 people were treated at an area hospital for complaints ranging from sore throats to streaming eyes, to difficulty breathing. The source and the composition of the cloud have never been determined, but the event is a reminder that hazardous materials can cause a range of medical issues—one of the most serious being respiratory emergencies.












