The Radioactive Hazard Suits  are standard protective wear designed to insulate users from hazardous radioactive material.
On at least one case, the original Ghostbusters were required to don hazmat suits. In 1997, Egon Spengler took them out of storage and had the Extreme Ghostbusters wear them for their stake out at the Isotope Research Center. The suits were rather itchy but necessary to protect the team from the effects of the Radioactive Ghost. Egon also wears one whenever he goes to procure radioactive material like Uranium-237.