Carcinogens and Highly Toxic Substances

Carcinogens are substances that may cause or increase growth of tumors in humans. For the purposes of the Lab Safety Manual, carcinogens are substances identified by OSHA, the International Agency for Research on Cancer (IARC), National Toxicology Program, or the American Conference of Governmental Industrial Hygienists (ACGIH) as a carcinogen or potential carcinogen.

Chemical toxicity is simply the capacity of a substance to cause harm to the body. Highly toxic substances are those with an oral LD50 < 50 mg/kg, or a lethal concentrations < 200ppm, or any chemical with unknown properties.

The risk from chemical carcinogens is greater or less depending on the quantity, the chemical properties or the intended operation. High-risk situations are those that involve the use of a highly potent chemical carcinogen, large quantities of chemical carcinogens, use of compounds with high vapor pressure or procedures that have a high potential for aerosol production or contamination. Operations such as blending or manipulation of powders are high-risk situations. In low-risk situations, the minimum safeguards are strict adherence to good laboratory practices. Personnel with medical condition, such as depressed immune response or steroid cytotoxic drug treatment, that makes them unusually susceptible to possible harmful effects of a carcinogen must be excluded from any area where accidental exposure might occur. Some carcinogens are reproductive hazards as well, meaning that they may change the DNA of sex cells or interfere with the development of the unborn child.

Carcinogens, reproductive hazards, and highly toxic substances must be handled according to the following guidelines.

Safe Handling

1. Exposure to identified carcinogens should be avoided as much as possible.
2. Use and store as little as reasonable.
3. Substitute these substances with less hazardous materials if possible.
4. Store and transport carcinogens in secondary containers
5. All work with volatile carcinogens or carcinogens in solid or powdered form shall be completed in a vented fume hood or closed system. If work is done in a vented hood, the system should remain on at all times, even when no work is being performed.
6. If work must be accomplished outside of a vented fume hood or closed system, proper respiratory protection must be worn. In order to wear respirators, the respiratory protection plan must be adhered to and lab workers must be fit tested. Contact EHS if carcinogens must be handled outside of a fume hood and for fit testing services.
7. The work area where procedures involving carcinogens are to be performed must be adequately labelled as such.
8. The work area should be covered with stainless steel trays, uncracked glass plates, dry absorbent plastic backed paper or the like. This work area should be disposed of or decontaminated after use. If additional safety precautions are deemed necessary, these should be posted at the work area as well.
9. Wash hands and arms immediately after working with these chemicals.