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UCLA Home / Campus Safety / Environment, Health & Safety / Chemical Safety

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Particularly Hazardous Substances and Other Reactive Chemicals

This article provides information about working safely with:

Particularly Hazardous Substances

Particularly Hazardous Substances (PHS) is defined by Cal/OSHA as any chemical that may be a select carcinogen, reproductive toxin, and/or acutely toxic. Careful handling and stringent controls of these chemicals are essential to protect workers and the environment from contamination.

Personal Protective Equipment (PPE)

  • At a minimum, safety goggles, lab coats, long pants, closed toe shoes, and gloves should be worn while handling PHS.
  • Review the specific chemical’s material safety data sheet (MSDS) and standard operating procedures (SOP) for additional PPE and glove selection.

Engineering Controls

  • Use a chemical fume hood or glove box when practical.
  • Never work in a manner that could lead to workers exceeding regulatory exposure limits.
  • Keep the laboratory door closed at all times.

Storage Requirements

  • Segregate PHSs in a designated location.
  • Store tightly capped and seismically secure.
  • Use secondary containment.
  • Label chemical bottles, work areas and storage areas.

Maintain a Specific Work Area

  • Designate an entire laboratory, specific work bench, or a chemical fume hood and only work with PHS’s in this area.
  • Limit access to PHS work areas.
  • Keep chemical quantities as small as practical.
  • Work on a chemically impervious surface (stainless steel, dry absorbent plastic backed paper, or chemically resistant epoxy surfaces).

Decontamination is Key

  • Decontaminate in a glove box or fume hood when practical.
  • Decontaminate all work surfaces at the conclusion of each procedure and at the end of each day.
  • Decontaminate all equipment before removing them from the designated area.
  • Decontaminate PPE.
  • When done, immediately remove gloves, and wash hands and arms with soap and water.

Waste Disposal Procedures

Dispose of all non-radioactive chemically contaminated waste through the UCLA Hazardous Chemical Waste Program.

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Water Reactive Chemicals

Water reactive materials are those that react violently with water. The alkali metals such as sodium, potassium and lithium react with water to produce heat and flammable hydrogen gas, which can ignite or combine explosively with atmospheric oxygen.

Personal Protective Equipment (PPE)

  • Safety goggles, lab coats, long pants, closed toe shoes, and gloves should be worn while working with water reactive chemicals.
  • Review the specific chemical’s material safety data sheet (MSDS) and standard operating procedures (SOP) for additional PPE and glove selection.

Engineering Controls

  • Many water sensitive chemicals will liberate hydrogen when they react with water. The use of a fume hood is recommended to prevent the buildup of combustible gases.
  • A glove box may be used to handle water sensitive chemicals when a dry atmosphere is required.

Storage Guidelines

  • Store in a cool and dry location.
  • Segregate water reactive chemicals from all other chemicals in the lab.
  • Isolated water reactive chemicals with the use of a waterproof or water-resistant barrier (such as a water-tight secondary container) to protect the materials from water in the event the sprinkler system is activated elsewhere in the facility.
  • Label chemical bottles, work areas and storage areas.

Maintain a Specific Work Area

  • The area should be clearly marked or posted to indicate the material being stored.
  • Access to the reactive materials storage area should be restricted.

Waste Disposal Procedures

All materials contaminated with water sensitive chemicals should be disposed of as hazardous waste.

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Pyrophoric Chemicals

For pyrophoric materials, oxidation of the compound by oxygen or moisture in air proceeds so rapidly that ignition occurs. Many finely divided metals are pyrophoric and their degree of reactivity depends on factors such as particle size, the presence of moisture and the likelihood of metal oxide formation. Various other reducing agents, such as metal hydrides, alloys of reactive metals, metal salts and iron sulfide, are also pyrophoric.

Engineering Controls

Glove boxes should be used to handle pyrophoric chemicals if inert or dry atmospheres are required.

Storage Guidelines

  • Pyrophoric chemicals should be stored under an atmosphere of inert gas or under kerosene as appropriate.
  • Do not store pyrophoric chemicals with flammable materials or in a flammable storage cabinet.
  • Store these materials away from sources of ignition. Minimize the quantities of pyrophoric chemicals stored in the laboratory.
  • Label chemical bottles, work areas and storage areas.

Waste Disposal Procedures

All materials contaminated with pyrophoric chemicals should be disposed of as hazardous waste.

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Peroxide Forming Chemicals

Peroxide forming chemicals are a class of compounds that have the ability to form shock-sensitive explosive peroxide crystals. The peroxides that form are less volatile than the solvent itself and thus tend to concentrate. This is particularly dangerous if peroxides are present during a distillation, where the applied heat to the concentrated solution may trigger a violent explosion. Equally dangerous is to allow a container of this material to evaporate to dryness, leaving the crystals of peroxide at the bottom of the container.

Personal Protective Equipment (PPE)

  • Safety goggles, lab coats, long pants, closed toe shoes, and gloves should be worn while working with water reactive chemicals.
  • Review the specific chemical’s material safety data sheet (MSDS) and standard operating procedures (SOP) for additional PPE and glove selection.

Engineering Controls

A fume hood may be used to minimize chemical exposure.

Storage Guidelines

  • Peroxide formers should be stored away from heat and light in closed vessels, preferably in the container furnished by the supplier.
  • Label all peroxide forming chemicals with the date received, date opened, and expiration date.

Waste Disposal Procedures

  • Dispose of peroxide forming chemicals according the chemical’s class as  described on the PFC Flyer.
  • If there is suspicion that peroxide is present, do not open the container or disturb the contents. Call Environment, Health and Safety (EH&S) at (310) 794-5569 to arrange for disposal. If the material is a peroxide former, test the contents before use. There are numerous methods for testing for peroxides. A test for peroxides should only be attempted if it is certain that no danger will result from moving or opening the container. Call EH&S Hotline at (310) 825-9797 for more information.

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Laboratory Safety Division
Email: laboratorysafety@ehs.ucla.edu | Phone: (310) 825-5689 | Fax: (310)-825-7076


Address
501 Westwood Plaza, 4th Floor
Box 951605
Los Angeles, California 90095-1605

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