Costco operates more than 800 warehouses around the world, so you can imagine how important it is to make sure each building is operating as efficiently as possible. To address our environmental impact, we have a program that clearly spells out smart practices involving energy and water use, waste disposal and more.

It's called STAR—Sustainability Technical Assistance Review. STAR is part of our sustainability initiatives, meant to protect the environment and create better efficiencies, all while reducing expenses.

STAR formulates practices and standards in the warehouses in five key areas:

Environmental compliance. This helps our locations follow environmental regulations and ensures that required documentation is available when inspections occur.

Water usage. This covers everything related to water, from leaks in the restrooms (see "A case study") to collecting stormwater.

Waste diversion. We have a goal to divert 80% of what might otherwise end up in a landfill, by reducing waste through donations, recycling and composting.

Energy consumption. Smart practices, maintenance and automated controls can reduce needless use of lights, heating and cooling systems, and other equipment.

Emissions. For us, reducing electricity use reduces emissions. Our refrigeration system is a big focus, along with smaller measures such as using door curtains in the cooler sections.

The program is overseen by regional specialists who work with their local warehouses. At the warehouse level, all staff are expected to follow STAR practices in daily operations. Those guidelines are posted in employee breakrooms, and best practices and updates are shared monthly through the STAR News bulletin.

Warehouse employees conduct their own STAR audits to gauge their success, which are followed up by regular formal audits by the regional specialists. The goal is to earn a star for each area of focus and become a "5-STAR warehouse."

Operating our warehouses in an environmentally responsible manner is a critical requirement for us. With so many warehouses worldwide, a small step such as using motion sensors to regulate lighting in offices can add up to a significant overall savings, both financially and environmentally.