hazmat suit
A hazmat suit (hazardous material suit) is a full body protective suit designed to protect the user from chemical, biological, nuclear or radiological hazards.
Most of them cover from head to toes and some are completely airtight.
They can be used with a gas mask to filter external air. Those with "positive pressure" (to guard against any fissure of the suit) have a balloon-like appearance.
May be seen at use during acts of terrorism, plagues, the apocalypse or post-apocalypse scenarios. Their users might be doctors or members of public forces.