Detecting diacetyl vapor in the workplace Detecting diacetyl vapor in the workplaceThe Owlstone Chemical Agent Monitor (OCAM) detects diacetyl, a common industrial chemical that is used in foodstuffs such as microwave popcorn as a synthetic butter flavor. Inhalation of diacetyl has been shown to cause bronchiolitis obliterans (AKA popcorn lung or popcorn workers lung), a potentially fatal disease in which the bronchioles are narrowed by scar tissue and inflammation.