This paper studies the 2022 Callao Oil Spill in order to highlight the main issues associated with the mens rea of ecocide. Described as the largest ecological disaster in Peruvian history, the spill was caused by a rupture in an underwater pipeline the day after a volcanic eruption in Tonga. However, important questions surface relating to whether it would be feasible and fair to hold Respol (the oil company) accountable under international criminal law (ICL), despite an apparent lack in mens rea. This paper ultimately suggests that national law be utilised in conjunction with the International Criminal Court (ICC) by separating ecocide into three distinct crimes of varying levels of culpability: First-Degree Ecocide will be criminalised within the ICC and will relate to environmental destruction committed with intent. Second degree ecocide will prosecute acts committed with recklessness and will be criminalised under either international or national criminal law. Finally, Third-Degree Ecocide will be incorporated into national law and will prosecute acts committed with criminal negligence such as the Callao Oil Spill. This model will uphold the severity of ICL being reserved for the most heinous crimes making it favourable politically, whilst a wider scope of conduct will be punishable under national law, therefore maintaining the deterrent effect of the crime.