Gas grenades and the Gas Generator Cargo Item create a cloud of gas in a module. Any character in a module with a gas cloud at any point during their phase is subject to its effects. At the end of a Phase that character must make an Athletics skill check of 11 or are affected by the gas as if struck by a needler loaded with that toxin (see page 97). See page 151 for gas and gas dissipation at the end of the Phase.