By Kevin Shanks, D-ABFT-FT

1,1-Difluoroethane (DFE) is a chemical compound that belongs to the family of hydrofluorocarbons, also known as HFCs. DFE has a chemical formula C2H4F2 and is a colorless, odorless gas at room temperature and is commonly used as a refrigerant (HFC-152a or R-152a) in air conditioning and refrigeration systems. It is also used as a propellant in aerosol products, such as cleaning sprays for electronics, computer keyboards, and other sensitive equipment. DFE has a relatively low environmental toxicity and does not deplete the ozone layer, therefore is considered a more environmentally friendly alternative to older refrigerants like CFC-12 (dichlorodifluoromethane) because it has a lower global warming potential (GWP). 

Chemical Structure of 1,1-difluoroethane (DFE)
Drawn by Kevin G. Shanks (2025)

The pharmacology of DFE is primarily related to its toxicological effects, as it is not used for any therapeutic or medical application. It is often misused by individuals seeking to experience a high through inhalation, sometimes called “huffing”, which can be highly dangerous and lead to severe health consequences. The substance acts as a volatile anesthetic that depresses the central nervous system leading to a sedative effect via the GABAA and glutamate receptors. Symptoms of acute exposure to DFE are coughing, wheezing, difficulty breathing, drowsiness, dizziness, light-headedness, headache, nausea, euphoria, and loss of coordination. In more severe cases, it can cause slurred speech, altered judgement, unconsciousness, pulmonary edema, suffocation, and death. Chronic exposure to DFE may lead to more long-term effects, including potential neurological damage and heart damage, including coronary disease, angina, and arrhythmias, and potential psychological addiction. 

Electronic cleaning spray with DFE as an ingredient  Images by Kevin G. Shanks (2025)

There have been several case reports of DFE toxicity and fatality published in scientific literature over the years. In reports published by Broussard et al. and Hahn et al., 3 adults died in vehicle accidents and had blood DFE levels ranging from 35-86 mcg/mL. In another report published by Frazee et al., two men were found dead after using DFE – they had postmortem blood DFE concentrations of 61 and 230 mcg/mL. In another report published by Vance et al., 14 adults who died following acute ingestion of DFE had postmortem blood concentrations ranging from 3-380 mcg/mL.  

As DFE is not a pharmaceutical medication or substance approved for use in the human body, there is no amount considered safe for use, therefore, there is also no unequivocal corresponding postmortem blood concentration that is considered therapeutic, toxic, or fatal. All postmortem blood concentrations can and should be considered relevant in a medical-legal investigation surrounding impairment, toxicity, and/or fatality. 

Axis Forensic Toxicology tests for DFE by gas chromatography with flame ionization detection (GC-FID) under order code 46590, and has just added the screen to the Comprehensive Panel with Analyte Assurance™. Minimum sample size is 0.5 mL. Due to the previously mentioned lack of relevancy of postmortem blood concentrations, all results are reported as qualitative (positive or negative). No quantitation is performed. 

As always, if you have questions about DFE and how it may have played a role in your medical-legal investigation, please reach out to our subject matter experts by email ([email protected]) or phone (317-759-4869, Option 3).

References

• Randall C. Baselt. Fluorocarbons. Disposition of Toxic Drugs and Chemicals in Man.12th Edition. Pages 878-880. 
• Larry Brousard, Barry S. Levine, Sarah Kerrigan. Chapter 31. Inhalants. Principles of Forensic Toxicology. 5th Edition. Pages 561-568. 
• L. Brousard, T. Brustowicz, T. Pittman et al. Two traffic fatalities related to the use of difluoroethane. Journal of Forensic Science, 42: 1186-1187 (1997).
• T. Hahn, J. Avella, and M. Lehrer. A motor vehicle accident fatality involving the inhalation of 1,1-difluoroethane. Journal of Analytical Toxicology, 30: 638-642 (2006).
• C.C. Frazee III, S. Fleming, and U. Garg et al. Huffing: Two deaths involving 1,1-difluoroethane. Society of Forensic Toxicologists Annual Meeting, 2010. 
• C. Vance, C. Swalwell, and I. McIntyre. Deaths involving 1,1-difluoroethane at the San Diego County Medical Examiner’s Office. Journal of Analytical Toxicology, 36: 626-633 (2012).