BALTIMORE (WJZ) — A retired anesthesiologist is walking to all 30 Major League Baseball stadiums across the country to bring awareness to patient and health worker safety.

Dr. Dave Mayer serves a leadership role at MedStar Health.

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He has put in 1,100 virtual miles across the U.S. with 16 stadiums to go.

He says people don’t realize preventable medical harm is the third leading cause of death in the U.S.

Saturday’s nine-mile walk was to Camden Yards.

If you’d like to join Dr. Mayer, download the Charity Miles app and select the Patient Safety Movement Foundation.