I regularly take my grandson to the Eureka National Children's Museum in Halifax, West Yorkshire as we have an annual pass. The day after my last three visits I got a red, itchy rash on the back of my hand. When you visit Eureka they stamp the back of your hand, I'm assuming they do this so you can come and go as you please during your visit.
I contacted Eureka to let them know I believe I had a reaction to the ink they are using. The response I received was very abrupt, defensive and ignorant. They specified the exact ink they use (Trodat 7011 Black), stated it was water-based and dermatologically tested, and that was it! At the very least I expected them to confirm they would cease the use of the ink while they investigate thoroughly.
I contacted Trodat, the manufacturer of the ink Eureka say they are using, and to quote their exact response "Our 7011 ink is designed to be used on porous surfaces such as paper or cardboard and has not been tested for use on skin". Further, a quick Google search and I found the EC Safety Data Sheet for Trodat 7011 Black Ink, and that makes very interesting reading, essentially confirming the ink can cause skin irritation.
If I have indeed had a reaction to the ink used at Eureka, it's possible others may have had a similar experience, but may not have made the connection. I do hope Eureka will now cease the use of their hand stamp and employ an alternative procedure. If you take your children to Eureka and they ask to stamp your hand, my suggestion would be to decline.