An ‘unofficial’ alert is spreading through social media today over the treatment with ethylene oxide of nasal swabs used in PCR tests for Covid-19. Ethylene oxide is, says Wikipedia, “too dangerous for direct household use” and “a very hazardous substance” which at room temperature is “flammable, carcinogenic, mutagenic and irritating”. It is nonetheless commonly used to sterilize products used by laboratories. The ‘alert’ spreading over social media is calling repeated PCR testing into question on the basis that it ‘cannot possibly be safe’. The Resident has tried getting a technical explanation from laboratories in the Algarve and Lisbon but has so far been consistently told that personnel “are not able to answer these questions”.