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Safe Use of Environmental Rooms

Follow these guidelines for safe use of environmental rooms.

Because environmental rooms have contained atmospheres, release of toxic substances from spills or vaporization poses potential occupational health and safety hazards to occupants.

Environmental rooms, generally built for the growth of cells or organisms, are engineered to control temperature and humidity levels.

Designed with limited or no mechanical ventilation, environmental rooms typically have closed air circulation systems that rely on the opening and closing of the room's door to bring in fresh air, as compared to laboratories which receive 6 or more air exchanges per hour through the building ventilation system.

Hazard evaluation

Evaluate the possible hazards of the materials and processes you intend to use in an environmental room, with particular attention to inhalation hazards.

Hazard control

Because environmental rooms have limited or no mechanical ventilation, release of any toxic substance into an environmental room presents a hazard to occupants, and potential cross-contamination of research projects.

Because hazardous vapors and fumes are not actively removed from the environmental room environment, work involving any hazardous materials should only be done in closed systems.

Take great care to control hazards and ensure a safe working environment:

  • Prevent the release of gases or aerosols at all times.
  • Use a less hazerdous product that can perform the same task, if possible.
  • Do not perform work in environmental rooms with these materials and equipment:
    • Flammable solvents
    • Corrosives
    • Asphyxiants (e.g., nitrogen and carbon dioxide)
    • Open flames (e.g., Bunsen burners)
  • Use an oxygen monitor if required. If EH&S determines that a project may suppress oxygen levels in an environmental room, an oxygen sensor will be required.

Safety training

The principal investigator (PI) or a knowledgeable designee must provide appropriate safety training, including the basic laboratory safety topics:

  • Follow general chemical safety guidelines at all times.
  • Inform employees about the safe use of environmental rooms.
  • Explain possible routes of exposure of hazardous material, as appropriate:
    • Skin contact
    • Eye exposure
    • Inhalation
  • Provide personal protective equipment and engineering controls, and train employees in their proper use.
  • Keep training records on file, including:
    • Information covered
    • Date
    • Names
    • Employee signatures

Emergency preparedness

Prohibited storage materials

Never store these materials in an environmental room:

  • Flammables: Flammable vapors (acetone, ethanol, methanol, etc.) could accumulate in an environmental room leading to dangerous conditions. Transfer buffer, for example, typically contains methanol. The best practice is to add methanol just before use.
  • Corrosive materials: Corrosive material can corrode cooling coils in the refrigeration system, causing Freon leaks. Examples: Acids, bases, sodium hypochlorite (bleach), halogens, and phenol.
  • Compressed gas cylinders: Compressed gas cylinders present a serious hazard if an undetected leak occurs. Asphyxiant gases can displace oxygen due to the low ventilation rate, causing an oxygen-deficient work environment. Cylinders may also corrode or rust if stored at an incorrect temperature, creating an additional hazard.
  • Dry ice: Undetected carbon dioxide vapors from dry ice could fill an environmental cold room and possibly cause an oxygen-deficient environment.
  • Food and drink: Do not store food and drink, including beer, in environmental rooms, even temporarily. Designate a Laboratory Clean Area outside the environmental room for this purpose.

Mold Contamination and Remediation

Mold is a serious indoor-air quality health issue.

Prevent mold.

  • Remove old culture plates and tubes (a food source for mold and mildew).
  • Remove all cardboard. Mold and mildew can easily grow on old or damp cardboard. Use plastic containers or foil to store light-sensitive items.


  • Contact your lab supervisor about corrective action if mold appears.
  • Work with your lab and all other occupying labs to remove and or decontaminate the supplies, equipment, surfaces, etc. that show any evidence of mold.
  • If the mold reoccurs quickly, contact the Department Safety Officer for assistance in scheduling a deeper decontamination of the cold room evaporators and condensing units with a mold-remediation company and coordinate this with Facilities Management. 

Good housekeeping

Maintain a safe and functional environmental room:
  • Dispose of unused or old chemicals.
  • Clearly delineate and label the space assigned to your lab.
  • Schedule routine checks to clean and remove legacy materials (e.g., tubes, samples, expired media/kits) as part of your lab procedures. 

Repairs and inspections

For more information, contact an EH&S Research Assistance Program specialist.

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