Centre of Behavioural and Forensic Toxicology, Institute of Legal Medicine, University of Padova, Via Falloppio 50, I-35121 Padova, Italy

Overall evaluation of circumstantial, anatomical and histopathological as well as microbiological and toxicological data indicated that the cause of both deaths was methanol intoxication by oral intake (methanol concentrations were 0.95 g/l, 0.80 g/l, 0.83 g/l, 0.90 g/l, and 0.60 g/l in Subject A's urine, heart blood, femoral blood, bile, and gastric content respectively ; 3.54 g/l, 3.70 g/l, and 3.58 g/l in Subject B's heart blood, femoral blood, and gastric content respectively).

In an attempt to identify the source of methanol exposure, judicial authorities subsequently asked for new comparative toxicological analyses of the above autopsy biological specimens and of samples of a liquid labelled as "methanol", confiscated later in the factory where the two men were employed.

A method based on headspace Solid-Phase Microextraction (SPME) coupled with Gas Chromatography-Mass Spectrometry (GC-MS) was developed to assay for possible low-boiling (volatile) substances in biological specimens and confiscated liquids. Another GC/MS method was developed to analyse ether extracts of the same samples, to search for possible high-boiling substances.

Toxicological findings indicated that the confiscated liquid was in fact methanol, containing the volatile impurities isobutyl alcohol and nitromethane and less than 1% of ricin oil, the latter characterized by the presence of three steroids: campesterol, stigmasterol, and beta-sitosterol. These impurities were due to chemical products used for model-making propellents manufactured by the factory. All autopsy biological specimens from both subjects also contained detectable amounts of isobutyl alcohol, nitromethane, and the above three vegetal steroids.

These findings indicated that the confiscated "methanol" represented the most probable source of fatal exposure for both subjects.