10-20 Tension in forehead, dilation of skin vessels. 20-30 Headache and pulsating temples. 30-40 Severe headache, weariness, dizziness, weakened sight, nausea, vomiting, prostration. 40-50 Severe headache, plus increased breathing and pulse rates, asphyxiation and prostration. 60-70 Coma, convulsions, weak respiration and pulse.
Death is possible.
70-80 Slowing and stopping of breathing, death within hours. 80-90 Death in less than 1 hour. 90-100 Death within a few minutes.