To assess the safety of commercially available OC spray in use by law enforcement agencies nationwide, both OC spray and positional restraint in human subjects were examined to determine if OC exposure by itself or in combination with positional restraint resulted in any significant respiratory compromise as measured by pulmonary function testing and assessment of oxygenation and ventilation. Study subjects performed four different experimental trials over two separate days in a pulmonary function testing laboratory in random order: placebo spray exposure followed by sitting position, placebo spray exposure followed by restraint position, OC spray exposure followed by sitting position, and OC spray exposure followed by restraint position. Prior to exposure, baseline spirometry measurements were obtained by pulmonary function testing. After exposure, repeat spirometric measurements were performed at 1.5 and 10 minutes. After a 1-hour rest, study subjects performed a second experimental trial. Completing the study were 34 individuals, 24 men and 10 women. No evidence was found that OC spray inhalation and exposure in human subject resulted in any respiratory compromise. Moreover, there was no evidence of hypoxemia or hypercapnia as a result of OC exposure. In fact, OC spray appeared to slightly increase ventilation. In the restraint position, declines were noted in pulmonary function typical for prone maximal restraint body position but no evidence was found of clinically significant spirometric abnormalities or differences between OC spray and placebo groups. The authors conclude that OC spray exposure and inhalation do not result in significant risk for respiratory compromise or asphyxiation. 61 endnotes and 8 exhibits