Personnel working in the areas of the NRU reactor at CRNL where they might come into contact with radioactive material that might contaminate their clothing were required to change from the normal clothing into designated clothing which was then monitored for contamination and washed in a special laundry. In NRU this could involve a complete set of clothing including undergarments, socks and coveralls. To ensure that an employee might not accidentally forget and wear the clothing outside of the reactor, the undergarments and socks were an unforgettable bright red colour.