Summary: The risks associated with the use of laboratory chemicals must be well understood prior to their use in an experiment. As many chemicals have multiple hazards, ensure to review the safety guidance for all hazard classes that may apply.

Definition:
Carcinogens are chemicals or physical agents that cause cancer or tumor development, typically after repeated or chronic exposure. Their effects may only become evident after a long latency period and may cause no immediate harmful effects.

Further, Cal/OSHA (8 CCR 5191) defines a “select carcinogen” as a substance or agent that meets one of the following criteria:

1. It is regulated by Cal/OSHA as a carcinogen.
2. It is listed under the category, “known to be carcinogens” in the Annual Report on Carcinogens published by the National Toxicology Program (NTP)(latest edition); or
3. It is listed under Group 1 (“carcinogenic to humans”) by the International Agency for Research on Cancer (IARC)
4. It is 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:
   1. 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;
   2. After repeated skin application of less than 300 mg/kg of body weight per week; or
   3. After oral dosages of less than 50 mg/kg of body weight per day.

Examples:
Carcinogens used in Stanford University laboratories include: Methylene chloride, benzene, formaldehyde, and acrylonitrile.

Summary: The risks associated with the use of laboratory chemicals must be well understood prior to their use in an experiment. As many chemicals have multiple hazards, ensure to review the safety guidance for all hazard classes that may apply.

Per 29 CFR 1910.1200 App B, a compressed gas is defined as a gas stored at pressures of 29 psi gauge or higher, which remains wholly gaseous at -50°C (-58°F). Related classifications include liquefied gases and dissolved gases, which are defined as follows:

• Liquefied gas: A gas, stored at pressures of 29 psi gauge or higher, which is partially liquid at temperatures above -50°C (-58°F).
• Dissolved gas: A gas which is dissolved in a liquid solvent at pressures of 29 psi gauge or higher.

Characteristics:

Examples:

Information on Toxic Gases:
For additional information on gases classified as toxic gases and management responsibilities, go to https://ehs.stanford.edu/reference/toxic-gas-ordinance-tgo-data-table

Summary:The risks associated with the use of laboratory chemicals must be well understood prior to their use in an experiment. As many chemicals have multiple hazards, ensure to review the safety guidance for all hazard classes that may apply.

Corrosive materials cause irreversible destruction of living tissue through chemical action at the point of contact. As corrosive chemicals can be liquids, solids, or gases, corrosive effects most commonly affect the skin, eyes, and respiratory tract.

Examples:
Corrosive materials used in Stanford University laboratories include: Liquids such as acids and bases, bromine, and hydrogen peroxide; gases such as chlorine and ammonia; and solids such as phosphorous and phenol.

Hydrofluoric Acid:
For work with hydrofluoric acid, see SU’s Information on Hydrofluoric Acid.

• One special property of both cryogenic liquids and dry ice is that they undergo substantial volume expansion upon evaporation or sublimation, which can potentially lead to an oxygen deficient atmosphere where ventilation is limited.

• Some cryogenic liquids can also pose additional hazards including toxicity and flammability (i.e. liquid carbon monoxide).

Examples:
Cryogenic liquids used in Stanford University laboratories include: liquid nitrogen, liquid helium, and liquid argon.

• The flash point of a substance is the temperature at which enough substance will vaporize to form an ignitable mixture with air.

Examples:
Flammable and combustible liquids used in Stanford University laboratories include: acetone, methyl alcohol, acetic acid, toluene, and glycerol.

• H300: Fatal if swallowed
• H310: Fatal in contact with skin
• H330: Fatal if inhaled

Examples:
Highly acutely toxic chemicals used in Stanford University laboratories include: Acrolein, Arsine, Nitrogen dioxide.

• Explosives: Lead azide, nitroglycerin
• Peroxide formers: Isopropyl ether, sodium amide, diethyl ether, styrene
• Water Reactives:Alkali metals (lithium, sodium, potassium), calcium carbide
• Pyrophorics:Grignard reagents (RMgX), metal powders (e.g., Al, Co, Fe, Mg, Mn, Pd).

Reproductive Toxins List:
Under CA Proposition 65, the State of California maintains a list of known chemicals causing reproductive toxicity. For the updated list, refer to: https://oehha.ca.gov/proposition-65/proposition-65-list#files

Examples:
Chemicals that are reproductive or developmental hazards include: chloroform, benzene, arsenic, and mercury compounds.

Stanford University’s Reproductive & Developmental Health Protection Program:
Personnel planning to use reproductive toxins can get more health-related information and further consultation via: https://ehs.stanford.edu/topic/health-wellness/reproductive-and-developmental-health-protection.

1. Toxic gases regulated by Santa Clara County (e.g., diazomethane, hydrogen cyanide, hydrogen fluoride (anhydrous), nickel carbonyl)
2. Dimethylmercury

Granting Prior Approval:
For additional information on methods for granting prior approval, go to section 5.2 of the Chemical Hygiene Plan.