Nickel ions can be released by some Nickel-containing materials. Prolonged direct contact with Nickel ions can cause skin sensitization and lead to allergic contact dermatitis. BS EN 1811:1998+A1:2008 states that nickel is the most frequent cause of contact allergy in Europe.

This has been designed as a quick in-house swab test to check for the Nickel ions from components that will come into direct and prolonged contact with skin. 

MSDS:-

https://tinyurl.com/yy45aqrc

https://tinyurl.com/yymyh8y3