Brian Capron, 1 B.S. and Barry K. Logan, 1, * Ph.D. Toluene-Impaired Drivers: Behavioral Observations, Impairment Assessment, and Toxicological Findings ABSTRACT: Toluene is an aromatic hydrocarbon solvent frequently abused for its euphoric and intoxicating properties. This report describes a series of six cases involving drivers arrested for driving under the influence who subsequently tested positive for toluene. Case data including driving behavior, physiological signs and symptoms, evidence of impairment, and toxicology findings were reviewed. Blood toluene concentrations in the drivers ranged from 12 to 45 mg ⁄ L (median 23 mg ⁄ L, mean 25 mg ⁄ L, SD 12.1 mg ⁄ L). All drivers were determined to be intoxicated, and displayed symptoms including balance problems, confusion and disorientation, loss of coordination, and inability to follow instructions. They also displayed horizontal but not vertical nystagmus, elevated pulse and blood pressure, and lower body temperature. These findings are consistent with prior reports that subjects with blood toluene concentrations above 10 mg ⁄ L are invariably under the influence and their driving skills are affected. KEYWORDS: forensic science, toxicology, toluene, impaired driving, driving under the influence of drugs, inhalant abuse, drug recognition expert Toluene is an aromatic hydrocarbon solvent present in many household and industrial chemicals, including cleaning solvents, paints and paint strippers, and glues. Toluene-containing products are abused for their euphoric, disorienting, and intoxicating effects, in a practice known as ‘‘huffing’’ or ‘‘solvent sniffing’’ in which the subject inhales the fumes from a solvent-soaked rag or bag (1). As these materials are readily and inexpensively obtained, the prac- tice of solvent abuse is widespread, particularly among school-aged children, and youths without the means to buy alcohol. A recent study reports lifetime rates of inhalant use in 5th, 7th, and 9th grade children in the United States and Australia approaching or exceeding the rates of marijuana use (2). The intoxicating effects of toluene including impairment of cognitive and psychomotor functions would be expected to result in deficits in driving perfor- mance. There have been a few reports of the specific appearance, driving behavior, and performance of individuals intoxicated as a result of toluene inhalation, which have included quantitative analysis of toluene in blood samples. We describe a series of tolu- ene-related impaired driving cases, in which driver behavior and performance in standardized field sobriety tests (SFST) or Drug Recognition Expert (DRE) examinations (four cases) were reported. Methods Blood samples were screened by Enzyme Multiplied Immunoas- say Technique (EMIT Ò , SYVA ⁄ Siemens, Deerfield, IL) for cocaine metabolite, opiates, benzodiazepines, barbiturates, cannabinoids, amphetamines, phencyclidine, propoxyphene, methadone, and tricy- clic anti-depressants. Acidic and basic extracts were prepared and screened by gas chromatography with flame ionization, mass selective, and nitrogen ⁄ phosphorus detection according to methods described elsewhere (3). Volatiles were screened and quantitated by gas chromatography with headspace autosampling, and the identity of aromatic hydrocarbons confirmed qualitatively by headspace gas chromatography with full scan mass selective detection. Standards were prepared fresh because toluene is lost from specimens by diffusion into headspace, by absorption into rubber stoppers, and possibly by other mechanisms (4–6). Toluene stock standard solu- tions were prepared in methanol (10%), and diluted out in deion- ized water to concentrations of 8.6, 21.5, 43, and 86 mg ⁄ L. Blood (0.2 mL) or aqueous standard and internal standard solutions (2.0 mL) (0.3 mL n-propanol and 20 g sodium chloride, diluted to 2 L with deionized water) were dispensed into headspace vials, and sealed with 20 mm Teflon-lined caps. Samples were analyzed by gas chromatography (6890 gas chromatograph, Agilent, Santa Clara, CA) on a 30 m DB-ALC-1 0.53 mm i.d., 3 lm film thick- ness (J&W ⁄ Agilent). The method has a limit of detection of 0.5 mg ⁄ L, and a limit of quantitation of 2 mg ⁄ L, and was linear up to 86 mg ⁄ L(R 2 = 0.995). The procedure was free from interfer- ences from other common volatile organic solvents, including ben- zene and o-, m-, p-xylenes. Toluene was baseline resolved from the internal standard (n-propanol) with a relative retention time of 1.31. Case Reports Six drivers suspected of driving under the influence were contacted by police officers of various agencies in the State of Washington. The following observations were recorded, and results of the DRE examinations are listed in Table 1. Table 1 also records the time dif- ference between arrest and blood collection, when known. Case 1 A 37-year-old male subject was contacted by police after being involved in a single vehicle collision in a parking lot. He had a 1 Washington State Toxicology Laboratory, 2203 Airport Way S., Seattle WA 98134. *Current address: NMS Labs, 3701 Welsh Rd, Willow Grove, PA 19090. Received 22 April 2008; and in revised form 17 June 2008; accepted 13 July 2008. J Forensic Sci, March 2009, Vol. 54, No. 2 doi: 10.1111/j.1556-4029.2009.00986.x Available online at: www.blackwell-synergy.com 486 Ó 2009 American Academy of Forensic Sciences