Sam MacIlwaine, climbing.com: ‘California Nutrition Startup Launches New Protein Chalk for Climbing’

Over a six-month period, researchers monitored the lungs of climbers who bouldered at the gym, without a mask on, for at least two hours per day once a week. They found that the average climber inhales close to one milligram per cubic meter per hour of magnesium carbonate particulate matter. That’s nearly twice the U.S. Workplace Exposure Limit of half a milligram per cubic meter per hour.

I thought the headline was nutty until I read this bit. Ingesting protein sounds better than magnesium!