WASHINGTON—Investigating a sudden uptick in nationwide on-the-job somnolence, the United States Occupational Safety and Health Administration released a study Monday showing that the majority of late afternoon sleepiness in the American workplace is in fact caused by an undetected carbon monoxide leak. “Our investigations found that a lack of focus, weariness, or general disinclination to perform at a job after normal lunch hours is most likely a sign that an employee is breathing in colorless, odorless, noxious fumes,” said lead researcher Mario Garrison, noting that over half the people who are feeling any kind of exhaustion or sluggishness at their place of employment between the hours of noon and 3 p.m. are being slowly poisoned at their desks or workstations. “Employees who become sleepy and close their eyes during the afternoon are in danger of never opening them again. The buildup of gas can be slow, as carbon monoxide is slightly lighter than air, so it may go unnoticed the entire morning. But make no mistake: From your first workplace yawn, you could be dead within an hour.” Garrison suggested that anyone who was feeling even the slightest bit tired in the afternoon hours at their place of employment should take the rest of the day off.