Perchloric Acid Guidelines

Acronyms

  • WHMIS – Workplace Hazardous Materials Information System
  • PI – Principal Investigator
  • PPE – Personal Protective Equipment
  • SDS – Safety Data Sheet (formally MSDS, Material Safety Data Sheet)
  • ORM – Office of Risk Management
  • HSR – Health, Safety, and Risk Management

Scope

This procedure is to be used when handling perchloric acid and perchloric acid mixtures. It does not replace the standard SDS provided for use with this chemical. The SDS must be current and updated within the past 3 years. Please consult the SDS for further information and precautions.

perchloric acid hazardous logo

Hazards

  • Perchloric acid is an extremely corrosive strong acid and is flammable or explosive under certain conditions
  • Concentrations in water at room temperature under 72% have oxidative and corrosive properties similar to other mineral acids
  • Increasing the temperature or increasing concentration to above 72% will result in a drastic increase in oxidative and corrosive properties
  • Anhydrous perchloric acid left sitting for a few days can spontaneously and explosively decompose at room temperature
  • Drying agents (example:acetic anhydride) added to perchloric acid can cause the formation of anhydrous perchloric acid and should be avoided
  • Vapors can condense on surfaces and inside fume hood ventilation, depositing explosive, shock-sensitive perchlorate salts
  • Contact of liquid or vapor with most organic materials and reducing agents results in fire or spontaneous explosion
    • Examples of organic materials include paper or cotton
    • Examples of reducing agents include many lithium reagents or carbon monoxide
    • Mixtures with nitric acid and cellulose are explosive
    • Mixtures with dimethyl sulphoxide are explosive
    • Mixtures with ferrous sulphate are explosive

Preparatory procedures

Before beginning work with perchloric acid, ensure that the following items have been gathered as part of an emergency kit in case of spills or accidental exposure:

  • Printed SDS from manufacturer or supplier, updated within the past 3 years
  • Pre-printed signage to be put on doors in case of spills, indicating that perchloric acid has been spilled and not to enter the lab
  • Appropriate neutralizing agent (such as an inorganic base like sodium carbonate)
  • Non-organic absorbents in case of spills (such as sand, however please note that the University of Ottawa spill kits do not contain sand)
  • Plastic sealable bags of various sizes that are both airtight and watertight (as contaminated materials stored in these bags are to be neutralized and thoroughly wetted to prevent spontaneous ignition)
  • Magnesia/glycerol paste for topical first aid
  • Milk of magnesia for ingested first aid
  • (Optional) Materials and chemicals necessary for perchlorate contamination tests, such the diphenylamine test or the methylene blue test
    • Diphenylamine: Dropper filled with diphenylamine sulfate solution. This solution can be made with 1 g diphenylamine dissolved in 10 mL 18 N sulfuric acid.
    • Methylene blue: Dropper filled with 0.4% solution of methylene blue in water.

Training

All research personnel are required to undergo safety and health training before working in the laboratory. They must complete an online WHMIS training and the Lab Safety Training course.

The University of Ottawa provides WHMIS, Lab Safety, and Health and Safety Awareness trainings that are mandatory for all laboratory workers. Training records must be kept, including the training offered, who was trained, who administered the training, and when this training occurred. Additional, non-mandatory trainings include the Fire Safety and Spill Response trainings.

Personnel planning to work with perchloric acid should receive training from experienced lab members or their PI on proper usage, handling, and disposal/clean-up. It is recommended that specific written procedures for each lab also be developed for normal use and emergency scenarios such as spills. The University of Ottawa offers Spill Response Training for personnel who wish to have it.

Handling perchloric acid

Perchloric acid is incompatible with a number of chemicals and must never be used with or stored near the following:

  • Acetic acid
  • Acetic anhydride
  • Alcohols
  • Aniline
  • Antimony compounds (trivalent)
  • Bismuth
  • Dehydrating agents
  • Diethyl ether
  • Formaldehyde mixtures
  • Fluorine
  • Glycerine
  • Glycols
  • Glycol ethers
  • Hydroiodic acid
  • Hydrochloric acid
  • Hypophosphites
  • Ketones
  • Lead oxide mixtures
  • Nitrogen triiodide
  • Nitrosphenol
  • Organic matter (paper, wood, charcoal, rags, cotton…)
  • Sodium iodide
  • Sulfoxides and sulfur trioxide

Storage

Concentrated perchloric acid should be stored in an acid cabinet with other inorganic acids, away from organic chemicals and reducers. Secondary containers should be used, made of glass, porcelain, ceramic, or other non-absorbing, non-combustible material. Do not store over extended periods of time. Anhydrous perchloric acid (>85%) should never be stored at room temperature for more than a few days, as there is significant risk of spontaneous decomposition or explosion. Anhydrous perchloric acid showing any discolouration MUST be disposed of immediately. All perchloric acid waste containers should be kept separate from other waste, complete with a separate and properly filled out University of Ottawa hazardous materials label. Do not touch a damaged or discoloured container, as it may be unstable or shock-sensitive.

Personal protective equipment (PPE)

All work with perchloric acid should be done in a fume hood wearing the following personal protective equipment (PPE):

  • A face shield is required when performing reactions with perchloric acid or when handling perchloric acid at concentrations higher than 70%
  • Gloves with appropriate chemical rating are required
    • A suggestion of approved materials are
    • Longer gloves (gauntlets) are required when working with anhydrous and >85% perchloric acid
    • Gloves are to be inspected prior to and during use
    • Use proper glove removal technique
    • Dispose of used gloves ONLY in provided waste disposal container
  • An approved chemical apron over a lab coat is required
  • No exposed skin is allowed

Note that perchloric acid can contaminate PPE over time. Care should be taken when handling used PPE, and it should be treated as a hazardous material. When disposing of PPE exposed to perchloric acid, treat as hazardous waste.

Handling

  1. All operations involving perchloric acid must be conducted in a fume hood
    • NO other organic chemicals or oxidizable materials should be present in the perchloric acid fume hood at any time
  2. Do not handle perchloric acid on a wooden surface or around oxidizable materials, which may ignite spontaneously or explode after contact with perchloric acid liquid or vapor
  3. Treat wet digestions with nitric acid before adding perchloric acid to destroy any easily oxidizable material
  4. Personal protective equipment (PPE) must ALWAYS be worn when handling perchloric acid
  5. Transfer perchloric acid over a suitable containment tray to limit extent and spread of spillage and facilitate clean-up and disposal
  6. NEVER work with perchloric acid while alone in the lab. There should always be a second person both aware of the dangers of perchloric acid and in the laboratory if any emergencies should arise. If you are working after hours, follow the After Hours Policy outlined by the University of Ottawa

Accidental release/spills

If at any point there is a spill and the operator believes their safety is in danger, contact Protection at ext. 5411 immediately. Follow the Researcher Checklist and Spill Response Procedures for spills.

  • If perchloric acid is spilled outside the fume hood or there is a large spill in the fume hood:
    1. Evacuate the area immediately
    2. Close the doors
    3. Place signage on the doors of the hazardous material
    4. Contact Protection (ext. 5411) from a nearby landline if possible
    5. Wait for Protection to arrive
    6. Continue with the regular Spill Response Procedures
  • If a small amount of perchloric acid is spilled in the fume hood and the laboratory staff understand the hazards and feel comfortable mitigating the spill:
    1. Ensure that the correct PPE is worn
    2. Inspect gloves for deficiencies
    3. Neutralize spill with sodium carbonate or another neutralizing agent
    4. Soak up spill with an inorganic absorbent and collect for disposal
    5. Do NOT use organic material such as paper towels or rags to clean up spills
      • If they are accidentally used, immediately douse with water and seal in a plastic bag for disposal
    6. Neutralize spill area again and rinse
    7. Waste should be kept separate as designated perchloric acid waste
    8. Contact the Hazardous Waste team for immediate disposal of the chemical waste
  • If perchloric acid is spilled onto organic or combustible material, immediately spray material and area with water and prevent from drying to ensure that risk of fire or explosion is mitigated. Seal contaminated material in a plastic bag with water and dispose of as chemical waste.
  • Surfaces can be tested for possible perchloric acid or perchloric salt contamination. See laboratory written procedures for testing instructions
    1. Diphenylamine test can be used and solution will turn black if contamination is present
    2. Methylene blue test can be used and a violet precipitate will appear if contamination is present

Perchloric acid fume hoods

Perchloric acid fume hoods are designed specifically for use with this chemical. The fume hood and ducts are made of stainless steel, and the equipped exhaust air scrubber system present in the ductwork sprays water on any fumes or vapors present.

Note: The University of Ottawa does NOT currently have any perchloric acid fume hoods. This section is for information only.

Usage, clean-up and special precautions

  • All reactions and procedures involving heated or anhydrous perchloric acid must be performed in a designated perchloric acid fume hood
  • Do not allow organic or combustible materials to be stored in this fume hood
  • Ensure that no crystals are formed in ventilation or anywhere else in fume hood, as they are shock-sensitive and explosive
  • Wash down fume hood after each use, following manufacturer guidelines to prevent chemical deposits

First aid and security measures

Burns from perchloric acid can spread rapidly and be very painful. All labs containing perchloric acid should have magnesia/glycerol paste, as well as Milk of Magnesia in their first aid kit.

In case of skin contact

  1. Wash affected area under running water for 15 minutes or until chemical is removed
    • If the spill is on the body, use the emergency shower
    • If victim is wearing contaminated clothing or gloves, remove them after the first 5 minutes and continue to wash for 10 minutes or until chemical is removed
  2. Apply magnesia/glycerol paste to the affected area
  3. Call Protection (x5411) for medical assistance
  4. Bring printed SDS to doctor for emergency treatment

In case of eye contact

  1. Wash with copious amounts of water for at least 15 minutes while holding eyelids apart
  2. Do not allow victim to rub eyes or keep them closed
  3. Call Protection (x5411) for medical assistance
  4. Bring printed SDS to doctor for emergency treatment

For inhaled perchloric acid vapors

  1. Remove the individual from the affected area and administer oxygen if breathing is difficult
  2. Call Protection (x5411) for medical assistance
  3. Bring printed SDS to doctor for emergency treatment

In case of ingestion

  1. Do not induce vomiting
  2. Wash out mouth with water
  3. Drink water, followed by Milk of Magnesia
  4. Call Protection (x5411) for medical assistance
  5. Bring printed SDS to doctor for emergency treatment

In case of fire

Many hazardous byproducts are produced in a perchloric acid fire, including chlorine gas and hydrochloric acid. In case of fire, note that there is still a significant risk of explosion and ignition of other chemicals. Other chemicals mixing into the fire will increase this risk. The University of Ottawa offers a Fire Safety Training for personnel who wish to take it.

  • Evacuate area and call Protection
  • To extinguish, use large volumes of cold water, dry sand, alcohol-resistant foam, or carbon dioxide
  • Beware of hazardous vapors formed, wear self-contained breathing apparatus

Resources

  • Faculty of Science HSR Website
  • ORM Website
  • Biosafety Office
  • Incident Report
  • SDS for Perchloric Acid
  • Hazardous Waste Procedures
  • Concordia University Perchloric Acid Safety Guidelines
  • Hazardous Laboratory Chemicals Disposal Guide
  • University of Illinois Perchloric Acid Guidelines
  • British Columbia Ministry of Energy and Mines Guideline for the Use of Perchloric Acid and Perchloric Acid Fume Hoods

Questions? Contact the HSR Team at pbera@uottawa.ca or extension 6425

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