“…�-propiolactone was not reported to be found in smoke or pyrolysis products, but was included in the table due to its toxicity and to the reported presence of other lactones. The literature (Sax 1979) indicates it decomposes rapidly at its boiling point of 15�°C, so it may not survive the pyrolysis process if it were to be formed. � propiolactone also is known to have a short half life in water and to polymerize upon standing at room temperature (NTP 1996b ), so it could also transesterify with the other organic esters, acids, and alcohols present in the pyrolysis oils.…”