Primary party organisations were key engines driving the complex process through which mass repression spread across the USSR, providing the institutional framework in which the social tensions of the mid-1930s could become entangled with the political initiatives of the leadership. PPO records thus offer a unique vantage point for following the gradual transformation of ordinary, if tense, social conflict into a lethal political crisis. They also demonstrate the significant extent to which the party rank-and-file remained a distinct actor deriving its understanding of the repressions from its own lived experience as filtered through its political outlook, in this way placing its own mark on events. In industry, this experience consisted primarily of workplace conditions and the permanently tense relations between workers and managers.