Poison ivy doesn’t mess around

I had a poison ivy snafu recently. When researching it, I discovered that urushiol oil (the stuff on poison ivy, oak, and sumac that causes all the trouble) is serious business:

• Only 1 nanogram (billionth of a gram) is needed to cause a rash.
• The average person is exposed to 100 nanograms per exposure.
• 1/4 ounce of urushiol is all that is needed to cause a rash in every person on earth.
• 500 people could itch from the amount covering the head of a pin.
• Specimens of urushiol several centuries old have been found to cause dermatitis in sensitive people.
• 1 to 5 years is normal for urushiol oil to stay active on any surface including dead plants.

Reminds me of the old chestnut about how all of the world’s covid particles would fit in a soft drink can.