Have a long history of little adverse effect on the lungs and do not produce significant organic disease or toxic effect when exposures are kept under reasonable control
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}