Photo credits

Photographs are used under Creative Commons licences via Wikimedia Commons and have been cropped and resized.

• Petrochemical site, Wesseling (Germany) — CEphoto, Uwe Aranas, CC BY-SA 3.0
• Petrochemical plant, Cologne (Germany) — CEphoto, Uwe Aranas, CC BY-SA 3.0
• Waalhaven container terminal, Port of Rotterdam — AgainErick, CC BY-SA 4.0
• Paraffin wax slab — Cjp24, CC BY-SA 3.0