Confined Space 15 : An enclosure that is difficult to get out of and limited or no ventilation. Examples are storage tanks, boilers, sewers and tank cars
US Department of Labor, Occupational Safety & Health Administration (OSHA), OSHA Office of Training and Education, Glossary of Terms, Construction Safety and Health Outreach Program, DC, USA 1996. http://www.osha.gov/doc/outreachtraining/htmlfiles /hazglos.html, Washington, (OSH - Amer) {516}