By VICE News June 12, 2016 | 10:25 pm A 29-year-old man killed at least 50 people and wounded 53 others at an Orlando nightclub early Sunday morning in the worst mass shooting in US history. President Barack Obama said from the White House that the shooting was an act of terror and hate, and represented an attack on all Americans.
Expected Duration. Carbon monoxide gas leaves the body the same way it got in, through the lungs. In fresh air, it takes four to six hours for a victim of carbon monoxide poisoning to exhale about half of the inhaled carbon monoxide in their blood.
Symptoms of CO poisoning. A headache is the most common symptom of mild carbon monoxide poisoning. Other symptoms include: 1  dizziness. 2  nausea (feeling sick) and vomiting. 3  tiredness and confusion. 4  stomach pain. 5  shortness of breath and difficulty breathing.