A 6-year retrospective study of the features of 79 consecutive completed suicides from exhaust fume inhalation (SEFI) in the Lothian and Borders region of Scotland was conducted. Full forensic autopsies with histological and toxicological studies were carried out. 2. The mean incidence is 2.0/100,000 population (M = 3.7; F = 0.4; P <> 0.001); increasing since 1990. The age peak is in the 35-44 years age group (especially among males) and a significant (P < 0.001) proportion reside in rural areas. 3. SEFI is significantly (P < 0.05) higher during spring and summer; outdoor locations are prevalent during summer. 4. Most (75.6%) of the victims were in current employment. Psychiatric illness (30.7%), problems in marriage or relationships (28.2%) and financial difficulties (16.7%) were the major associated socio-medical factors. 5. The mean carboxyhaemoglobin (COHb) saturation was 74 +/- 11.2%; fatal COHb saturation levels were still detectable in severely decomposed bodies. The blood alcohol concentration (BAC) in 37 of the victims ranged from 14-397 mg dl-1. No significant correlation exists between COHb saturation and the victim's age or BAC. 6. Attempts to reduce the incidence of SEFI must be directed principally to dealing with associated sociomedical problems. The reduction of the potential of vehicles to produce carbon monoxide and of directing exhaust fumes into the interior of the vehicle are important secondary preventative measures.
