Toxicity Profiles

RAGs A Format for Cyanide - CAS Number 57125

Cyanide is usually found joined with other chemicals to form compounds. Examples of simple cyanide compounds are hydrogen cyanide, sodium cyanide and potassium cyanide. Hydrogen cyanide is a colorless gas with a faint, bitter, almond-like odor. Sodium cyanide and potassium cyanide are both white solids with a bitter, almond-like odor in damp air. Cyanide and hydrogen cyanide are used in electroplating, metallurgy, production of chemicals, photographic development, making plastics, fumigating ships, and some mining processes. Cyanide can be produced by certain bacteria, fungi, and, algae and is found in a number of foods and plants. Cyanide occurs naturally in cassava roots, which are potato-like tubers of cassava plants grown in tropical countries. In the body, cyanide combines with a chemical to form Vitamin B12.

In large amounts, cyanide is very harmful to humans. Cyanides are readily absorbed by the inhalation, oral, and dermal routes of exposure. Exposure to high levels of cyanide in the air for a short time harms the brain and heart and may cause coma and death. Exposure to lower levels of cyanide for a long time may result in breathing difficulties, heart pains, vomiting, blood changes, headaches, and enlargement of the thyroid gland. Human consumption of large amounts of cyanide may cause deep breathing and shortness of breath, convulsions, loss of consciousness, and possibly death. Use of cassava roots as a primary food source in tropical Africa has led to high blood cyanide levels. Skin contact with cyanide can produce irritation and sores.

No suitable cancer bioassays or epidemiological studies are available to assess the carcinogenicity of cyanide. EPA has therefore placed cyanide in weight-of-evidence group D, not classifiable as to human carcinogenicity.

The following is a presentation of the toxicity information associated with Cyanide.

Noncarcinogenic Health Effects

• The Oral Chronic Reference Dose is 2.00E-02 (mg/kg-day).
• The Oral Chronic Reference Dose has a modifying factor of 5.
• The Oral Chronic Reference Dose has an uncertainty factor of 100.
• The Oral Chronic Reference Dose is based on the Philbrick et al. study from 1979.
• The Oral Chronic Reference Dose study critical effects are weight loss, thyroid effects, myelin degeneration.
• The overall confidence in the Oral Chronic Reference Dose is medium.
• The Dermal Chronic Reference Dose is 3.40E-03 (mg/kg-day).
• The Dermal Chronic Reference Dose is based on a gastrointestinal absorption factor of 0.1700.