By adopting environmentally-friendly approaches to surgery, hospitals can reduce their carbon footprint, cut health care costs and keep patients safe, according to a new study by Johns Hopkins researchers that offers some strategies for going green.

Health care facilities produce more than 6,600 tons of waste each day and more than 4 billion pounds every year. Only the food industry produces more waste, according to background information in the article. Cleaning and reusing tools once labeled for one-time use is one way to save costs and cut down on waste and Meredith wrote last year about hospitals efforts to do so.

But this new study appearing in the latest Archives of Surgery zeros in on the waste in surgical rooms. Consider that operating rooms and labor and delivery suites account for about 70 percent of hospital waste, according to the researchers. ORs are known for keeping sterilized equipment open -- even if it's never used -- and using expensive overhead lights.

They also do a poor job at disposing of medical waste. 

Surgical rooms often use two types of bags to dispose of waste: red bags for pathologic waste and clear bags for noninfectious waste, explains a release about the study. Nearly 90 percent of what ends up in the red bags -- which cost more to process -- could be tossed elsewhere, according to Dr. Martin A. Markey, an associate professor of surgery at the Johns Hopkins University School of Medicine and the study's author.

After a while that gets super expensive. "Although hazardous and regulated medical waste (equivalent to infectious waste) makes up only 24 percent of medical waste, it accounts for 86 percent of costs," the study concluded.