Resources and Support for Multiple Chemical Sensitivities, Environmental Illness, and Chemical Injuries in Canada

How To Conduct A Personal Test (or the Jar Test)

This material is adapted from Building Materials for the Environmentally Sensitive by CMHC. It is also based on my own experience. The book is a great help for anyone building a new house or renovating and is available for purchase through the CMHC website (the link to the book is towards the bottom of the page).

Exercise caution when conducting a personal test. Consult your physician. You are responsible for testing and using the materials.

NOTE: A personal test will help to determine if a product is tolerable or not, but it has limitations. Remember that testing a small sample is not the same as living with it over time especially if it is a material that is used extensively in the living space. Make sure to go slowly with this testing and to be cautious. You are exposing yourself to the VOCs in the materials.

The Jar Test is a very simple but effective way to gauge the tolerability of products or materials. Basically, by isolating materials in a glass jar, removing the lid and gauging any reaction you might have, tolerability levels to various items can be determined. It can be used for building supplies, fabrics, paper products or anything at all that you can fit in the jar.

IMPORTANT: If you are extremely reactive or sensitive, please see the added caution at the bottom of this page.

It is important that samples are placed in a clean glass jar which is free from odours. Ensure the jar lid is odourless so it doesn't mask or affect the test in any way. Make sure the lid fits tightly.

Try to replicate the conditions in which the the materials will be used. For example, if testing a material that needs to be cured (such as caulking), put some on a piece of aluminum foil, allow it to cure for the recommended time, and then place the sample in the jar. If testing grout that will be sealed, place the grout on the foil and when it has cured, apply the sealant, allowing the sealant to cure before placing the sample in the jar. The idea is to ensure that you are testing the material as it will be used in your living space.

Conduct the initial test in a place that is "odour-neutral" with relatively clean, unpolluted air and good ventilation.

Test one sample at a time and do so when you are well rested, relaxed, and free from distractions. Use your responses to judge whether the material is suitable for you.

Remember that sensitivity may develop after continuous and prolonged exposure to a material. It is possible that products that seem acceptable when tested may become problems later. Do not let this factor discourage you from testing. Initial reactions will screen out many unacceptable choices.

To determine if the material is viable at all, do the preliminary test, then do the Jar Test.


Preliminary test with a small sample

  • Hold a sample of the material at arm's length. Note any odour or sensory response. If an adverse reaction is observed, the material is probably not a good choice. Test other materials.
  • If no odour or reaction is noticed at arm's length. slowly bring the material closer to the body. Note any odour or sensory response. If an adverse reaction is produced, do not test the material any further. If no response is elicited, go on to the Jar Test.

The jar test

  • Place the sample in the jar. Seal tightly with the lid and place it in a spot exposed to the sun or in a moderately warm place for an hour or longer (not more than 100 degrees F).
  • Repeat the above steps holding the jar at arm's length with the jar partially open. (Just slide the lid to one side.)
  • If no odour or reaction is noticed, repeat the test with the jar completely open. Evaluate whether any odour is noticed or any body reaction occurs.
  • If the material passes the sealed jar test, a decision can be made whether to do more testing. This is especially important if the material will be used extensively inside the house.

Note: It can be helpful to have someone watch your reactions for those you might not note. For example, the head snapping back, even slightly, can indicate the material is affecting you. Having another person do this test can be illuminating, too. This reaction to something toxic seems universal. When we smell food that has soured or spoiled, our head automatically snaps back or pulls away. This same reaction can often be noted with materials that are offensive or toxic in general.

Further testing of small sample

Once the material has passed the Jar Test, try living with the sample for a time. Keep it close by in an area that you frequent. If you use your pc a lot, for example, keep the sample (out of the jar) on your desktop for a few hours. Note any reactions. If no reactions are noted, place the sample on your bedside table and sleep overnight with it there. Do this for a few nights.

Testing a larger sample

Obtain a larger sample of the material. Follow the basic test procedure, testing the material several times or for longer periods to ensure that it does not provoke negative reactions.

CAUTION: For those who are extremely sensitive: do your initial testing outdoors (if the outdoor ambient air is clean enough for you) on a calm day with no wind. Have another person perform the steps starting a certain distance away from you. For example, if you want to test a new computer mouse, have the person stand first 50 feet away and quickly remove the lid of the jar containing the mouse. Assuming you have no reaction, have them repeat this while moving a few feet closer to you. Go slowly. Once you determine it seems to be tolerated, then repeat the test indoors.

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