A spill is an accidental release of a harmful substance into the environment, including petroleum products, chemicals, sewage, or other hazardous materials. Spill response is governed by federal, provincial, and sometimes municipal regulations depending on the substance and location. Reporting requirements specify which spills must be reported and to whom—typically environment ministries and emergency services. Responsible parties must contain and clean up spills, with potential penalties for non-compliance. Municipalities respond to spills affecting local waterways, storm sewers, or public areas, often coordinating with provincial environment agencies. Major spills may trigger emergency response protocols. Transportation of dangerous goods regulations aim to prevent spills during transit. Historical contamination from past spills affects brownfield site redevelopment.