Bleloch's first post back in South Africa was as Chief Chemist to the Union Steel Corporation. He enlisted in the South African Engineering Corps at the outbreak of World War II, and was commissioned to compile a feasibility report on establishing a mustard gas plant on the farm Klipfontein near Kempton Park as part of the war effort. The production rate of 10 tons per day was not regarded as sufficient by the British principals and a second factory was established at Firgrove near Somerset West.[4] Once full production had been reached the project was placed under civilian management.