How might chemicals slip unnoticed across boundaries and through bodies in a range of material and bureaucratic registers? This article responds by extending emergent theorisations of ‘slipperiness’ into the nascent field of chemical geographies. Slipperiness offers a framing for chemicals that challenges and also situates contemporary managerial regimes that subscribe to universalised concepts such as pollution thresholds. Breaking slipperiness into four key characteristics - stealth, dynamism, persistence, and slippages - this paper draws on an empirical case study of Port Kembla, a heavy industry brownfield port in Australia, to outline how industrial chemicals have been instrumental in the port's ongoing relations with the broader residential community. This research takes place at a pivotal juncture in history when such sites are being actively repurposed to support decarbonisation infrastructures. The article hones in on four interrelated themes that emerged from the fieldwork as avenues for exploring the characteristics and consequences of chemical slipperiness. The first theme is the role of historical chemical contamination in maintaining port boundaries. The second explores how governance of contaminants is grounded in the concept of thresholds. The third examines the role of new energy transition infrastructure in disturbing and redistributing historical chemical accretions. The fourth theme is the knowability and visibility of chemical contaminants for residential communities in spatial proximity with the port. This paper develops the concept of bureaucratic slippage and focuses on the potential of voluminous understandings of space to overcome or challenge governance regimes that otherwise would fail to identify and manage contaminant risks.