An effect that can be expressed only as "...occurring'' or "not occurring'' (Finney, 1971). Typical examples of quantal effects are death or occurrence of a tumour
International Programme on Chemical Safety IPCS (A joint venture of the United Nations Environment Programme UNEP, the International Labour Organisation, ILO and the World Health Organization WHO), Glossary of Terms on Chemical Safety for Use in IPCS Publications, World Health Organization, Division of Environmental Health, World Health Organization, Geneva, Switzerland, ILO 1996-2010. http://www.ilo.org/legacy/english/protection/safew ork/cis/products/safetytm/glossary.ht, (IPCS Chem Sfty - Brit) {103}