TLC of post-explosion debris showed that in some cases PETN was accompanied by other compounds which reacted with Griess reagent. The possibility that these compounds could be lower nitrate esters of pentaerythritol (tri-, di- and mononitrate) was examined. Lower nitrate esters were obtained by hydrolysis of PETN and their structures were determined–following separation–by mass spectrometry and NMR. Chromatographic data of these esters matched data of the compounds which accompanied PETN in certain post-explosion cases. The dinitrate and trinitrate esters of pentaerythritol were isolated from post-explosion extracts and their structures confirmed by mass spectrometry and NMR.