Following are terms asccociated with chemical exposure that all science teachers should know. It is helpful to include these terms when discussing RAMP and safe chemical handling in the laboratory.
Allergen (sensitizer)
A chemical that causes an allergic reaction— that is, evokes an adverse immune response (could be a severe rash or respiratory distress).
Asphyxiant
A gas or vapor that can cause unconsciousness or death by suffocation due to lack of oxygen.
Autoignition temperature
The temperature at or above which a substance will spontaneously ignite or catch fire without a spark or flame.
Carcinogen
A substance that is capable of causing cancer.
Corrosive
A highly reactive substance that causes obvious damage to living tissue by chemical action. Examples of corrosive substances are strong acids, strong bases, and oxidizing agents.
Exposure
Direct contact with a hazard or chemical in a way that causes injury or harm.
Fetotoxicant
A substance that enters the maternal and placental circulation and causes injury or death to the fetus.
Flammable
A substance that easily catches fire. As defined by the GHS, a flammable substance is one that has a flash point at or above 73 °F (23 °C) and below 140 °F (60 °C). A highly flammable substance has a flash point below 73 °F (23 °C) and an initial boiling point above 95° F (35° C). An extremely flammable substance has a flash point below 73° F (23° C) and an initial boiling point below 95° F (35° C).1
Flash point
The lowest temperature at which a liquid or solid can produce a vapor sufficient to form an ignitable mixture in the air. The lower the flash point, the easier it is to ignite the material.
Mutagen
A substance capable of changing genetic material in a cell and thus increasing the frequency of mutations.
Runaway reaction
An unexpected event in which the rate of reaction increases significantly, resulting in a significant increase in temperature. The increase in temperature causes the rate of reaction to increase, further increasing the rate and tending to create an uncontrolled, often heat-producing, reaction.
Teratogen
An agent that can cause non-inheritable genetic mutations or malformations of an embryo or fetus. The agent can be a chemical substance, virus, or ionizing radiation.
Toxic
Any substance that has the capacity to produce personal injury or illness to humans through ingestion, inhalation, or absorption through any body surface, as defined by Federal Hazardous Substances Act (FHSA) regulation.
Acute toxicity
The adverse effects of a substance resulting from a single exposure or multiple exposures over a very short time span (less than 24 hours). Acute toxicity is usually determined by exposing animals to a given chemical to determine the lethal dose, 50% (LD50). This is an experimental measure determined by administering varied doses of a chemical by some route to animals, observing the percentage lethality at these doses, and extrapolating to estimate the dose that would kill 50% of the animals.
Chronic toxicity
Adverse effects resulting from long-term exposure, usually at lower levels, to a substance.
Types of Acute Toxicants
Asphyxiant
A gas or vapor that can cause unconsciousness or death by suffocation due to lack of oxygen.
- Examples: Carbon monoxide, methane, hydrogen sulfide
Irritant
A noncorrosive chemical that causes reversible inflammation at the point of contact with the skin.
- Examples: Acetone, heptane, ethyl acetate, sodium carbonate
Neurotoxicant
A chemical that interferes with the peripheral and central nervous systems.
- Examples: Mercury, lead, acetone, carbon disulfide
Organ toxicant
A chemical that adversely affects one or more organs or body systems.
- Examples: Toluene, carbon tetrachloride, arsenic, chlorine
Sensitizer/allergen
A chemical that produces its effects by evoking an adverse response in the body’s immune system.
- Examples: Formaldehyde, latex
Teratogen or fetotoxicant
A chemical that adversely affects the embryo or fetus.
- Examples: Ethanol, ethylene oxide, mercury compounds
Examples of Chronic Toxicants2
Carcinogen
- Examples: Ethylene oxide, Cr(VI) formaldehyde, arsenic
Neurotoxicant
- Examples: Carbon disulfide, hexane, lead, nicotine, arsenic
Organ toxicant
- Examples: Mercury, ethanol, beryllium, chloroform
1 Source: UNECE. Globally Harmonized System of Classification and Labelling of Chemicals, 2015. www.unece.org/fileadmin/DAM/trans/danger/publi/ghs/GHS_presentations/English/phys_haz_e.pdf (accessed Dec 1, 2015).
2 Source: Hill, R. H.; Finster, D. C. Laboratory Safety for Chemistry Students; John Wiley & Sons, Inc.: Hoboken, NJ, 2010; pp 4-1 to 4-34.