Explosions may occur if dry ice is placed in airtight transport containers

An error occurred in this letter by Sally Sharp and colleagues (17 February, p 434). In the second sentence of the fourth paragraph the wrong conversion factor was used to convert vapour pressure from bars to the SI unit of Pascals, the correct factor being 1 bar=10⁵ Pa. The sentence should read: “When warmed to 20°C solid carbon dioxide exerts a huge vapour pressure (5730 kPa [57.3 bar; not 28.7 Pa as published]), yet the safety data sheet of at least one manufacturer and the Health and Safety Executive's website (www.open.gov.uk/hse/hsehome.htm) contain no reference to the explosion hazard.”