Is Cytox 3522 (10% methylene-bis-thiocyanate) a human skin sensitizer?

Methylene-bis-thiocyanate is an antimicrobial agent in Cytox 3522 (American Cyanamid Corporation) and Nalco 206 (Nalco Chemical Company). Both are wide-spectrum industrial biocides. Cytox 3522 showed a strong sensitization potential in guineau pigs using the Guinea Pig Maximization Test and the Open Epicutaneous Test procedures. In spite of this, human sensitization has not been reported. This may be explained by several factors such as limited exposure, low-use concentration and a lack of diagnostic patch tests in selected patients.