Drierite Indicating

⚠ Danger ☠
Indicating drierite is a mixture of two chemicals. Calcium sulfate and cobalt II chloride. Calcium sulfate is not hazardous but cobalt II chloride is. As such indicating drierite is deemed a particularly hazardous substance (PHS) by EH&S and you need approval before using it. Throughout this SOP, you will see PHS where steps specific to particularly hazardous substances exist.

This chemical standard operating procedure (SOP) and the associated Safety Data Sheet (SDS) are for our safety. Read and understand both documents. If this is a paper copy, check for updated versions on the IsoLab website.


Indicating Drierite is used as a desiccant. We use it to absorb vapor water from air streams with our water vapor analyzers. The blue cobalt II chloride (CoCl2) turns light purple or pink when it has absorbed sufficient water.

Hazards - SDS

GHS Health Hazard Pictogram

May cause cancer by inhalation. May damage fertility or the unborn child. May cause an allergic skin reaction. May cause allergy or asthma symptoms or breathing difficulties if inhaled. Suspected of causing genetic defects.

Protection - SDS

Hierarchy of Controls
The Hierarchy of Hazard Controls. While you should consider Elimination and Substitution, this SOP assumes the bottom three are directly applicable and described in this section.

Engineering Controls

PHS - Indicating drierite should be used in a fume hood. Ensure the fume hood has proper air flow by checking the flow rate on the control panel and / or using a smoke match or wipe to visualize flow.

Administrative Controls

PHS - Make sure that anyone working near you is aware you are using indicating drierite and that cobalt II chloride is used as the indicator and is toxic.

Personal Protective Equipment (PPE)

PHS - Wear a laboratory coat, eye protection, and nitrile gloves while working with indicating drierite.

Handling - SDS

Keep container tightly closed when not in use.

PHS - Decontamination - Any glass or plastic ware should be rinsed and the rinse should go into your labeled waste container.

Storage - SDS

In general, indicating drierite is stored on the north wall of 303B shelf #7. Use MyChem, the UW EH&S chemical inventory database, for more lab-suite specific storage details.

Spills - SDS

Avoid dust formation. Don a respirator or evacuate if spilled outside a fume hood.

PHS - Exposure:

If the spill occurred in and is completely contained in the fume hood, close the sash and prepare yourself to clean it up. Clean up all material using wipes and paper towels. Discard all materials that have come into contact with Drierite into the designated waste container.

Use personal protective equipment. If a large spill is outside of fume hood, don a respiratory mask located in 303B near the balances in addition to a laboratory coat, nitrile gloves, and goggles. Avoid dust formation. Avoid breathing dust. Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided. Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.

If you need assistance or advice, use the IsoLab Emergency Contacts sheet.

Consult the EH&S Spill Poster and Exposure Poster

Waste - SDS

If you are cleaning up after a spill and have a bag of debris, ensure the bag is sealed and use multiple bags as needed. Complete an EH&S Hazardous Waste Label and adhere it to the bag. Here are instructions for how to label chemical waste containers. Labels are located in a drawer on the west wall of 303B near the door to the hallway.

Put all waste, solid or liquid, into a wide mouth plastic container. Options for waste containers can be found under the west sink in 303B. Complete an EH&S Hazardous Waste Label and adhere it to the bottle. Here are instructions for how to label chemical waste containers. Labels are located in a drawer on the west wall of 303B near the door to the hallway. Make certain to label as the components of indicating drierite (95% calcium sulfate and 5% cobalt II chloride).

Place the properly labeled container in one of the gray tubs near the hallway door of 303B. Segregate from other waste containers as appropriate.

Consult our generalized Chemical Waste Disposal SOP.

Chemical SOP Signature Required Sticker
This sticker is placed on all chemical containers that are deemed particularly hazardous and require approval before use.

Training - PHS

Indicating drierite is deemed a particularly hazardous substance - PHS by EH&S because it contains cobalt II chloride and you need approval before using it. Complete the list of requirements below before using this chemical.


  1. You must have completed Managing Laboratory Chemicals in the last three years. Login to check.
  2. Read and understand the SDS for indicating drierite.
  3. Read, understand, and digitally sign this SOP.
  4. Contact your Principal Investigator (PI) AND the Chemical Hygiene Officer (CHO) indicating that you have completed all prerequisites and await approval.


I have read and understood the present SOP and, before starting work outlined in the present SOP, I will complete all required training.

Last updated: 2021-06-23 09:03:58