wording 

"Apart from MIC the gas cloud may have contained phosgene, hydrogen cyanide, carbon monoxide, hydrogen chloride, nitrous oxides and carbon dioxide, either produced in the storage tank or in the atmosphere. All these gases, except carbon dioxide, are toxic." Carbon dioxide is toxic and significant enough levels (around 8% i think). It is just less toxic than the others. How could this be reworded so as to be clearer? Talk