a non_western constant vacuum is poisonous
gaseous_phosgene is poisonous_gas. gaseous_perfluoroisobutene is poisonous_gas. poisonous_gas is toxic_substance. poisonous_gas is not toxic_substance. toxic_gas is not gas. silver_chloride is toxic_substance. poisonous_gas is chemically_harmful_substance. silver_chloride is not toxic_substance. poisonous_gas is not gas.