By 1938, the Polish industry did not produce any machinery and equipment in explosion-proof version. It was not until that year that Zakłady Elektromechaniczne Rohn-Zieliński (Electromechanical Plant Rohn-Zieliński) in Cieszyn (now ME Celma SA) started preparing for the production of explosion-proof motors based on the license documentation of the Swiss company Brown Boveri. The motors were designed for mining industry.