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Particularly Hazardous Substances
The Wisconsin Department of Commerce enforces occupational safety regulations on University of Wisconsin System campuses. The Department of Commerce adopted the U.S. Occupational Safety and Health Administration's (OSHA) standard for Occupational Exposures to Hazardous Chemicals in Laboratories.
One of the requirements of the standard is that a laboratory's Chemical Hygiene Plan must include provisions for additional employee protection for work with particularly hazardous substances. The definition of particularly hazardous substances includes three categories:
- select carcinogens,
- reproductive toxins, and
- substances that have a high degree of acute toxicity.
The following are defined as select carcinogens by OSHA.
OSHA listed carcinogens.
- Methyl chloromethyl ether
- 3,3'-Dichlorobenzidine (and its salts)
- bis-Chloromethyl ether
- Vinyl chloride
- Inorganic arsenic
- Coke oven emissions
- Ethylene oxide
- Methylene chloride
Any substance listed under the category, "known to be carcinogens," in the Annual Report on Carcinogens published by the National Toxicology Program (NTP) (latest edition);
Any substance listed under Group 1 ("carcinogenic to humans") by the International Agency for Research on Cancer Monographs (IARC) (latest editions);
Any substance listed in either Group 2A or 2B by IARC or under the category, "reasonably anticipated to be carcinogens" by NTP, and causes statistically significant tumor incidence in experimental animals in accordance with any of the following criteria:
- After inhalation exposure of 6-7 hours per day, 5 days per week, for a significant portion of a lifetime to dosages of less than 10 mg/m3;
- After repeated skin application of less than 300 (mg/kg of body weight) per week; or
- After oral dosages of less than 50 mg/kg of body weight per day.
Unfortunately, no recognized list of known human reproductive toxins exists. OSHA specifically regulates only four agents based on their reproductive toxicity: dibromochloropropane (DBCP), lead, ionizing radiation and ethylene oxide. Handle all chemicals with caution. If you are working with an unfamiliar chemical, check the Material Safety Data Sheet (MSDS) or TOXNET (http://toxnet.nlm.nih.gov) to determine if the chemical is considered a reproductive toxin.
Substances with a High Degree of Acute Toxicity
OSHA does not provide very practical guidance on substances with a high degree of acute toxicity. The University of Wisconsin-Madison Safety Department provides its laboratories with the following guidance:
The OSHA Laboratory Standard does not list or define substances with a high degree of acute toxicity. The rule’s preamble (55 FR 3320) describes substances with a high degree of acute toxicity as those substances that are “fatal or cause damage to target organs as a result of a single exposure or exposures of short duration.“ Hydrogen cyanide, hydrogen sulfide and nitrogen dioxide are given as examples.
Remember, a chemical may be toxic by one of several routes of entry. To be classified as having a high degree of acute toxicity, the chemical must fall within any of the following categories...
- A chemical with a median lethal dose (LD50) of 50 mg or less per kg of body weight when administered orally to certain test populations.
- A chemical with an LD50 of 200 mg or less per kg of body weight when administered by continuous contact for 24 hours (or less if death occurs within 24 hours) to certain test populations (e.g., to the bare skin of albino rabbits weighing between 2 kg and 3 kg each).
- A chemical with a median lethal concentration (LC50) in air of 200 parts per million (ppm) by volume or less of gas or vapor, or 2 mg per liter or less of mist, fume, or dust, when administered to certain test populations (e.g., albino rats weighing between 200 and 300 gm each) by continuous inhalation for one hour, provided such concentration and/or condition are likely to be encountered by humans when the chemical is used in any reasonably foreseeable manner.
To determine if you use a substance with a high degree of acute toxicity that may require additional employee protection under the OSHA Laboratory Standard, consult the MSDS, the Registry of Toxic Effects of Chemical Substances (RTECS), or your campus Safety Department. TOXNET (http://toxnet.nlm.nih.gov) also provides useful information.
Some examples of chemicals with a high degree of acute toxicity include:
- diborane (gas)
- hydrogen cyanide
- hydrogen fluoride
- methyl fluorosulfonate
- nickel carbonyl
- nitrogen dioxide
- osmium tetroxide
- sodium azide
- sodium cyanide
Provisions for additional employee protection
The Chemical Hygiene Plan shall include the following element and shall indicate specific measures that the employer will take to ensure laboratory employee protection:
(e)(3)(viii) Provisions for additional employee protection for work with particularly hazardous substances. These include "select carcinogens," reproductive toxins and substances which have a high degree of acute toxicity. Specific considerations shall be given to the following provisions which shall be included where appropriate:
(e)(3)(viii)(A) Establishment of a designated area [see note];
(e)(3)(viii)(B) Use of containment devices such as fume hoods or glove boxes;
(e)(3)(viii)(C) Procedures for safe removal of contaminated waste; and
(e)(3)(viii)(D) Decontamination procedures.
[Note: Designated area means an area which may be used for work with select carcinogens, reproductive toxins or substances which have a high degree of acute toxicity. A designated area may be the entire laboratory, an area of a laboratory or a device such as a laboratory hood.]
University of Wisconsin-Madison. Particularly Hazardous Substances, Appendix D of the Chemical Safety and Disposal Guide.
University of Wisconsin-Milwaukee. Additional Laboratory Personnel Protection for Work with Particularly Hazardous Substances, Chapter 7 of UWM Chemical Hygiene Plan.
Princeton University. Particularly Hazardous Substances, Section 7J of the Laboratory Safety Manual.
Cornell University. Laboratory Safety Manual Chapter 9 - Particularly Hazardous Substances.
University of Medicine & Dentistry of New Jersey. Some Standard Operating Procedures (SOP) for particularly hazardous substances.
This publication was prepared for environmental, health and safety staff at University of Wisconsin System campuses, to assist in finding resources and information for regulatory compliance. It is not intended to render legal advice.
(Read full legal disclaimer.)