Torture by asphyxiation (Dry)

What is torture by asphyxiation?

There are three types of asphyxiation: 1. Dry asphyxiation (submarino, “the elephant”, bagging, hooding), 2. Wet asphyxiation (wet submarino, waterboarding), and 3. Positional asphyxiation (1). Please see separate Factsheet for waterboarding and positional torture. Torture by dry asphyxiation is the prevention of normal respiration by obstruction of the airways, pressure or ligature around the neck or by forced aspiration of dust, gas, cement etc. (2). Torture through asphyxiation by suffocation is increasingly used as a torture method (2). Torture by dry asphyxiation fits the definition of torture as per the UN Convention against Torture and should be considered an unacceptable form of treatment under any circumstance (3).

The UN Special Rapporteur on Torture, the European Court of Human Rights and the European Committee for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment (CPT) all deem dry asphyxiation as constituting torture (4–8)

In practice

In dry asphyxiation different methods are used to prevent normal respiration. This includes covering the head with a bag or mask, closure of the mouth and nose, pressure or ligature around the neck or forced inhalation of dust, cement, hot pepper, etc. (2). The material used to cover the airways may be contaminated with bodily fluids such as blood or feces, chilies or volatile liquids such as petrol  (1).

In a study from 2016 examining 45 ex- detainees in Spain, the authors found that of those who had been subjected to asphyxiation (47%), the majority had suffered dry asphyxiation (hood, bag)  (9). Another study from 2016 found that 7.5% of 67 female ex-political prisoners in Lebanon had been victims of dry asphyxiation (plastic bag) (10).

Dry asphyxiation has been documented as a common method of torture in many places around the world, including Spain, USA, the former Yugoslavia, Cambodia, the former Soviet Union, Lebanon and other countries in the Middle East and in Sub-Saharan Africa. Dry asphyxiation is often used in combination with other torture methods (10–13).

Health consequences

Dry asphyxiation is categorized as a ‘clean’ torture technique because it leaves no or few visible marks on the body (11) rendering it difficult to detect and to study.

Consequences of dry asphyxiation may include petechiae (pin-point sized skin bleedings caused by broken capillary blood vessels) on the skin and conjunctivae (eyes), bleeding from the ears or nose, mouth infections, acute or chronic respiratory problems, cerebral hypoxia (brain oxygen deprivation) leading to loss of consciousness, chronic cognitive impairment, brain damage, and even death (2,12,14,15).

Experiments of temporary hypoxia in healthy adults have shown that hypoxia causes severe cognitive deficits across all measured domains of cognitive function with effects on memory, processing speed, executive function, reaction time and cognitive flexibility. In addition, the participants reported feeling tired, and displayed loss of coordination, blurred vision, weakness, dizziness, irritability and restlessness (16).

Psychological consequences:
Only a few studies with small study populations have investigated the specific psychological long-term consequences of dry asphyxiation. The studies found an associated with panic disorder and a non-significant association with PTSD (10,17). However, the consequences of dry asphyxiation may be linked to the consequences of wet asphyxiation which consist of a range of long-term psychological effects including panic attacks, depression, post-traumatic stress disorder (PTSD) and personality changes (18).


Dry asphyxiation causes serious physical and psychological suffering with documented medical sequala. There is a need for comprehensive training of medical and legal professionals to understand the complexity of this kind of torture in terms of both health consequences and detection.

  1. Beynon J. ‘Not waving, drowning’. Asphyxia and torture: the myth of simulated drowning and other forms of torture. Torture Q J Rehabil Torture Vict Prev Torture. 2012;22 Suppl 1:25–9.
  2. United Nations, editor. Istanbul Protocol: manual on the effective investigation and documentation of torture and other cruel, inhuman, or degrading treatment or punishment. Rev. 1. New York: United Nations; 2004. 76 p. (Professional training series).
  3. OHCHR. Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment [Internet]. [cited 2018 Jun 1]. Available from:
  4. UNSRT. Report of the UNSRT, Sri Lanka [Internet]. 2008 Feb [cited 2019 Feb 12]. Report No.: A/HRC/7/3/Add.6-E. Available from:
  5. ECHR. Shishkin v. Russia [Internet]. 2011 Jul [cited 2019 Feb 12]. Report No.: Application no. 18280/04. Available from: /cases,ECHR,4e254a462.html
  6. ECHR. Shestopalov v Russia [Internet]. 2017 Mar [cited 2019 Feb 12]. Available from:
  7. CPT. Report to the Latvian Government on the visit to Latvia carried out by the European Committee for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment (CPT). 1999.
  8. CPT. 13th General Report on the CPT’s activities covering the period 1 January 2002 to 31 July 2003. 2003.
  9. Pérez-Sales P, Navarro-Lashayas MA, Plaza A, Morentin B, Barrios Salinas O. Incommunicado detention and torture in Spain, Part III: ‘Five days is enough’: the concept of torturing environments. Torture Q J Rehabil Torture Vict Prev Torture. 2016;26(3):21–33.
  10. Ghaddar A, Elsouri G, Abboud Z. Torture and Long-Term Health Effects Among Lebanese Female Political Prisoners. J Interpers Violence. 2016 Feb;31(3):500–14.
  11. Rejali DM. Torture and democracy. Princeton: Princeton University Press; 2007. 849 p.
  12. Moreno A, Grodin MA. Torture and its neurological sequelae. Spinal Cord. 2002 May;40(5):213–23.
  13. Morentin B, Callado LF, Idoyaga MI. A follow up study of allegations of ill-treatment/torture in incommunicado detainees in Spain. Failure of international preventive mechanisms. Torture Q J Rehabil Torture Vict Prev Torture. 2008;18(2):87–98.
  14. Ely SF, Hirsch CS. Asphyxial deaths and petechiae: a review. J Forensic Sci. 2000 Nov;45(6):1274–7.
  15. Pollanen MS. The pathology of torture. Forensic Sci Int. 2018 Mar 1;284:85–96.
  16. O’Mara S. The captive brain: torture and the neuroscience of humane interrogation. QJM Int J Med. 2018 Feb 1;111(2):73–8.
  17. Bouwer C, Stein DJ. Association of panic disorder with a history of traumatic suffocation. Am J Psychiatry. 1997 Nov;154(11):1566–70.
  18. Correa C. Waterboarding Prisoners and Justifying Torture: Lessons for the U.S. from the Chilean Experience. Hum Rights Brief [Internet]. 2007 Jan 1;14(2). Available from:

Researched and written by:
Marie My Warborg Larsen with contributions by Maha Aon, Jens Modvig, Marie Brasholt and Lisa Michaelsen.
September 2018
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