Smoke screens have been employed in sea and land warfare for many centuries for a variety of purposes. They have been used to conceal troop movements, to deceive the enemy as to combat strengths, point of attack, and preparations for offensive operations. During the Second World War all armies made use of smoke screns in their operations to a greater or lesser extent. Canada was no exception and was considered to be extremely innovative in the use of smoke equipment in ways for which it was not designed. The First Canadian Army first employed large-scale non-artillery-projected smoke screens during the campaign in Northwest Europe. For the first time, at least in the history of Canadian operations, units of trained specialists worked to lay down smoke screens in the field.