Poisons and Toxic Chemicals

Poisons, toxic chemicals, can refer to chemicals with acute toxicity or chromic toxicity. In addition, toxicity may target a specific organ. Highly toxic chemicals should be handled only by trained individuals and stored in a dedicated, labeled, and locked Toxics/Poisons cabinet. Experiments must be well planned and take place only in designated areas with limited access. Symptoms of exposure of these materials may vary. Review each SDS for the specific material being used and take note of the associated symptoms of exposure.

OSHA defines “Toxic” as a chemical falling within any of the following categories:

• A chemical that has a median lethal dose (LD50) of more than 50 milligrams per kilogram but not more than 500 milligrams per kilogram of body weight when administered orally to albino rats weighing between 200 and 300 grams each.
• A chemical that has a median lethal dose (LD50) of more than 200 milligrams per kilogram but not more than 1,000 milligrams per kilogram of body weight when administered by continuous contact for 24 hours (or less if death occurs within 24 hours) with the bare skin of albino rabbits weighing between two and three kilograms each.
• A chemical that has a median lethal concentration (LC50) in air of more than 200 parts per million but not more than 2,000 parts per million by volume of gas or vapor, or more than two milligrams per liter but not more than 20 milligrams per liter of mist, fume, or dust, when administered by continuous inhalation for one hour (or less if death occurs within 1 hour) to albino rats weighing between 200 and 300 grams each.

When working with highly toxic chemicals, you should not work alone. Always wear proper PPE and always wash your hands with soap and water when finished, even if gloves were worn. If you think you may have received an exposure to a poisonous substance, or may have accidentally ingested a chemical, seek medical attention immediately and/or call the Poison Control Center at 1-(800) 222-1222 or call 911 If possible, bring a copy of the SDS with you. Upon completion of seeking medical attention, complete an Incident Report.

Health hazards with Toxic Effects on Specific Organs

Substances in this category include:

• Hepatotoxins - i.e., substances that produce liver damage, such as nitrosamines and carbon tetrachloride, 
• Nephrotoxins - i.e., agents causing damage to the kidneys, such as certain halogenated hydrocarbons, 
• Neurotoxins - i.e., substances which produce their primary toxic effects on the nervous system, such as mercury, acrylamide and carbon disulfide, 
• Hematopoietic agents - e.g., carbon monoxide and cyanides which decrease hemoglobin function and deprive the body tissues of oxygen,
•  Pulmonary agents - e.g., asbestos and silica.

Symptoms of exposure to these materials vary. Staff working with these materials should review the SDS for the specific material being used and should take special note of the associated symptoms of exposure.

Irritants and Sensitizers

Irritants are defined as non-corrosive chemicals that cause reversible inflammatory effects on living tissue by chemical action at the site of contact. A wide variety of organic and inorganic compounds, including many chemicals that are in a powder or crystalline form, are irritants. The most common example of an irritant may be ordinary smoke which can irritate the nasal passages and respiratory system. Consequently, eye and skin contact with all laboratory chemicals should always be avoided.

A sensitizer (allergen) is a substance that causes exposed people to develop an allergic reaction in normal tissue after repeated exposure to the substance. Examples of sensitizers include diazomethane, chromium, nickel, formaldehyde, isocyanates, arylhydrazines, benzylic and allylic halides, and many phenol derivatives. Sensitizer exposure can lead to all of the symptoms associated with allergic reactions, or can increase an individual's existing allergies. Caution should be taken when using these chemicals. Use only in fume hood or gloveboxes. Do not use out in open benches or areas. Never have an open container of a sensitizer outside of a fume hood or space with proper ventilation. If you think you may have become sensitized to a chemical, seek medical attention immediately. If possible, bring a copy of the SDS with you. Upon completion of seeking medical attention, complete an Incident Report.