Spills on construction sites can arise from a number of sources and from a number of activities. Commonly used construction materials such as concrete, cement & grout all create a potential contamination risk in the immediate environment. Plant machinery also has the potential to leak oil and fuel during general maintenance and refuelling activities. Chemicals & hazardous substances should be stored within appropriate containers on any construction site.

Failure to prepare for a spill incident can have devastating effects on rivers, canals and other watercourses nearby. For example, excavations made for building foundations can create pathways for materials to quickly infiltrate the ground and drainage systems.