The European Parliament Scientific and Technological Options Assessment (STOA) published in 1998 “An Appraisal of Technologies of Political Control”[5] with extensive information on pepper spray and tear gas. They write:
"The effects of pepper spray are far more severe, including temporary blindness which lasts from 15-30 minutes, a burning sensation of the skin which lasts from 45 to 60 minutes, upper body spasms which force a person to bend forward and uncontrollable coughing making it difficult to breathe or speak for between 3 to 15 minutes."
For those with asthma, taking other drugs, or subject to restraining techniques which restrict the breathing passages, there is a risk of death. The Los Angeles Times has reported at least 61 deaths associated with police use of pepper spray since 1990 in the USA,.[6] The American Civil Liberties Union (ACLU) documented 27 people in police custody who died after exposure to pepper spray in California since 1993.[2][7][8] However, the ACLU report counts any death occurring within hours of exposure to pepper spray. In all 27 cases, the coroners' report listed other factors as the primary cause of death, though in some cases the use of pepper spray may have been a contributing factor.[2]
The US Army concluded in a 1993 Aberdeen Proving Ground study that pepper spray could cause "Mutagenic effects, carcinogenic effects, sensitization, cardiovascular and pulmonary toxicity, neurotoxicity, as well as possible human fatalities. There is a risk in using this product on a large and varied population".[9] However, the pepper spray was widely approved in the US despite the reservations of the US military scientists after it passed FBI tests in 1991. As of 1999, it was in use by more than 2000 public safety agencies.[10]