Hazardous Atmospheres

Hazardous Atmospheres

Earth's atmosphere is 78% nitrogen and 21% oxygen (plus 1% comprising a number of other gases). Visitors to other planets (and victims of lab accidents or death traps) might encounter other atmospheres, most of which are unsafe for humans without proper protection. Of course, "breathable air" for humans might be deadly for nonhumans, and vice versa!

Corrosive: The atmosphere reacts with exposed flesh. Those with the Sealed advantage are safe; those in sealed suits might be safe, but some gases eat away at seals. Small concentrations in otherwise breathable air require a roll at HT to HT-4 every minute to avoid 1 point of corrosion damage. Victims suffer coughing (see Afflictions) after los-ing 1/3 their HP, blindness (as the disadvantage) after losing 2/3 their HP. Atmospheres made up mostly of corrosive gases have effects comparable to immersion in acid (see Acid) and count as suffocating. Corrosives include ammonia and nitrides. Chlorine and fluorine are extremely corrosive and toxic!

Toxic: The atmosphere is poisonous. Individuals without respirators, Doesn't Breathe, Filter Lungs, etc. are susceptible. Ordinary airborne industrial pollutants might require a daily HT roll to avoid 1 point of toxic damage. Lethal gases would call for a HT-2 to HT-6 roll every minute to avoid 1 point of toxic damage. If such gases make up most of the atmosphere, they inflict at least 1d toxic damage per 15 seconds (no resistance possible) and count as suffocating. A typical toxic gas is carbon monoxide. Chlorine and fluorine are deadly in tiny concentrations, and also corrosive.

Suffocating: The atmosphere is unbreathable. For humans, this means it lacks oxygen. Those without Doesn't Breathe or an air supply start to suffocate (see Suffocation). Hydrogen, methane, and nitrogen are all suffocating. As noted above, an atmosphere made up mostly of corrosive or toxic gases is suffocating as well – but these usually kill so rapidly that suffocation becomes irrelevant.