Dirty water? Wastewater? Process-stream water? Nalco treats them all. The Ecolab subsidiary is the world's largest maker of chemicals used in water treatment for industrial processes (ahead of #2 GE Water and Process Technologies). Nalco's Energy Services segment is also #1 worldwide, ahead of Baker Petrolite; it provides fuel additives, oilfield chemicals, and flow assurance services to energy companies. The company's chemicals help clarify water, conserve energy, prevent pollution, separate liquids from solids, and prevent corrosion in cooling systems and boilers.