The petro-chemical industry is a critical infrastructure that is vulnerable to cybercrime. In particular, industrial process control systems contain many vulnerabilities and are known targets for hackers. A cyberattack to a chemical facility can cause enormous risks to the economy, the environment, and public health and safety. This gives rise to the question how corporate cybersecurity has developed; how it is governed; and whether it should be subject to public oversight. This paper presents a case study of the governance of cybersecurity in the petrochemical industry in the Rotterdam Mainport area in the Netherlands, which reflects the 'new governance' view that cybersecurity can best be governed through voluntary public-private partnerships. The paper finds however that actual collaborative governance is not developing in the petrochemical industry in the port of Rotterdam; that corporate awareness and investment in cybersecurity stay behind standards, and that cybersecurity is not included in regulatory inspections. The paper places these findings in the context of three problems often associated with 'new governance' particularly pressing in cybersecurity governance: a weak role of government in publicprivate collaborative arrangements; an expectation that businesses will invest in self-regulation even in the absence of incentives to do so, and a lack of information exchange. In the port of Rotterdam, these problems result in a lack of obligations and accountability pressure on petrochemical corporations, leaving on of the most important chemical industrial hazards of today, largely unregulated. Crime Law Soc Change (2017) 68:75-93