A substance that adversely affects one's health by causing injury, illness, or death. These are often marked with a skull and crossbones as shown on the right. A substance that counteracts the effects of a poison is called an antidote. Additional Info: A gas poisonous by inhalation is defined by 49 CFR 173.115 as "material which is a gas at 20 deg.C (68 deg.F) or less and a pressure of 101.3 kPa (14.7 psi) (a material which has a boiling point of 20 deg.C (68 deg.F) or less at 101.3 kPa (14.7 psi)) and which: (1) Is known to be so toxic to humans as to pose a hazard to health during transportation, or (2) In the absence of adequate data on human toxicity, is presumed to be toxic to humans because when tested on laboratory animals it has an LC50 value of not more than 5000 ml/m3 ... LC50 values for mixtures may be determined using the formula in Sec. 173.133(b)(1)(i) of this subpart“. A poisonous substance (other than a gas) is defined by 49 CFR 173.132 as a material "which is known to be so toxic to humans as to afford a hazard to health during transportation, or which, in the absence of adequate data on human toxicity: Is presumed to be toxic to humans because it falls within any one of the following categories when tested on laboratory animals (whenever possible, animal test data that has been reported in the chemical literature should be used): Oral Toxicity: A liquid with an LD50 foracute oral toxicity of not more than 500mg/kg or a solid with an LD50for acute oral toxicity of not more than 200 mg/kg. Dermal Toxicity: A material with an LD50for acute dermal toxicity of not more than 1000 mg/kg. Inhalation Toxicity: A dust or mist with an LC50 foracute toxicity on inhalation of not more than 10 mg/L; or A material with a saturated vaporconcentration in air at 20 deg.C (68 deg.F) of more than one-fifth of the LC50 for acute toxicity on inhalation of vapors and with an LC50 for acute toxicity on inhalation of vapors of not more than 5000 ml/m3 or Is an irritating material, with properties similar to tear gas, which causes extremeirritation, especially in confined spaces”. MSDS Relevance: Treat poisonous materials with respect! Read the MSDS sheet to find out what ways a poison can kill you -- is it by inhalation, ingestion and/or skin contact? What precautions should you take with the material? What kinds of personal protective equipment (PPE) are recommended? Remember to read the material label and MSDS if a poison is ingested. For example, it is sometimes bad to induce vomiting because some materials can cause additional chemical burns to the throat and esophagus upon regurgitation. If in doubt, contact the nearest emergency room or call the American Association of Poison Control Centers poisoning emergency number (800) 222-1222. Don't fool around with poisons. Treat them with great respect at all times. See also: Activated Charcoal, Antidote, Catharsis, Cytotoxin, Emetic, Mus (mouse), Swiss Poison Class, Toxic