TEXT: TREACHEROUS CONDITIONS
  By Andy Chambers
  The Underhive is an ever-changing environment: sludge flows and sump overspills can turn dry ground into swamp in
  hours, lighting failures can plunge whole areas of the hive bottom into darkness and the ground can suddenly fall away
  into a bottomless pit. Worst of all, terrifying hive quakes shake the whole area as the massive structure of the hive above
  slowly settles on its foundations.
  60
  12
  Sludgy Surface
  A thin layer of luminous green slime covers the tabletop.
  Models may move as normal but if they double their
  movement by running or charging in these conditions they
  must roll equal to or under their Initiative on a D6 or they will
  slip over and count as being pinned. Gantries and walkways
  aren’t slimy so models on them aren’t affected by this rule.
  13
  Slimy Film
  The whole area is covered with a horrible thin film of slime
  but it is nothing more than an annoyance. Continue the fight
  as normal.
  14
  Old Gunk Tank
  Sludge-dripping pipes and slimy grates indicate that this area
  was once a huge gunk tank of some kind but has long since
  been drained. Carry on with your fight as normal.
  15
  Old Gunk Tank
  Sludge-dripping pipes and slimy grates indicate that this area
  was once... Oh dear, it’s filling up! Set up the gangs and then
  roll a D6 for each model to see who gets gunked as the pipes
  and grates spew forth the disgusting slime. Models get
  gunked on a 1, 2 or 3 and count as being pinned at the start
  of the game, they may also fall if they’re within 1" of the edge
  of a structure or walkway. Just roll once for each model to see
  whether they are ‘gunked’, from then on the slime has no
  effect. Models that attempt to use tunnels or vents to sneak
  around the opposition must roll a D6 each: on a roll of 1, 2
  or 3 they are driven back from the gunk tank by rising slime
  and do not fight in the game at all.
  16
  Pit of Despair
  The entire level of the tabletop is covered with a seemingly
  bottomless layer of sludge. The whole game must be fought
  on the higher levels, though any models that fall from gantries
  and walkways onto the tabletop will not suffer any damage as
  their fall is cushioned by the sludge. Unfortunately, the model
  must also roll equal to or under their Strength on a D6 at the
  start of each of their turns. If they succeed, they can move at
  2" per turn to the nearest gantry and climb out. If they fail, the
  model is automatically swallowed and suffocates in the thick
  sludge (gloop!). Any equipment or weapons carried by
  models drowned in the slime is lost.
  21-26
  High Winds 
  Your fight is taking place near an intersection of gigantic air
  tunnels that feed cleaner air around the hive. Large domes
  can also generate their own micro-climates which create
  powerful air vortices in the right conditions. These swirling
  winds can make conditions on the gantries and walkways
  extremely dangerous.
  The Treacherous Conditions rules in this article bring just
  some of the many dangers of the Underhive into your games
  of Necromunda, and can be used in almost all of the scenarios
  in Necromunda. The one exception we came across is the
  Shoot-out scenario which takes place inside a settlement or a
  drinking hole, where the only really treacherous conditions
  are in the kitchens!
  Both players can agree not to use treacherous conditions if
  they want (wimps!) but otherwise they must be rolled for
  even if only one player wants to use them.
  Roll for treacherous conditions after the scenario has been
  chosen and the terrain has been placed but before players set
  up their gangs. The table uses a D66 roll in the same way as
  the Serious Injuries chart in Necromunda. Roll two dice: the
  first roll represents tens and the second units, so a roll of 1
  and 5 is 15, 6 and 3 is 63, and so on.
  Ratskins
  Ratskin Scouts and Ratskin Renegades are immune to all the
  effects of treacherous conditions. Ratskins are born and bred
  in the dangers of the Underhive so they learn how to avoid
  them or die at a very early age.
  11-16
  Bubbling slime
  Something extremely nasty has bubbled up from the Sump...
  11
  Sea of Goo
  A thick layer of stinking black slime covers the entire tabletop.
  Models have to wade through this disgusting gunge if they
  want to reach another gantry or walkway, and moving is
  extremely difficult in this glutinous slime. Movement is
  restricted to 2" per turn when wading. Models can’t double
  their movement by running or charging in the goo, as the
  disgusting stuff is too thick to move fast through. Gantries and
  walkways aren’t slimy so models on them aren’t affected by
  this rule.
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  61
  21
  Howling Winds
  The winds are so powerful that no one will climb onto a
  gantry or walkway. The game must take place entirely on the
  tabletop where there is more shelter. Players may not use
  vents to work their way around their opponent in howling
  winds.
  22
  Blustery Conditions
  Shooting is extremely difficult in such blustery conditions,
  especially over distances. Anyone firing a weapon at long
  range suffers an extra -1 to hit penalty. Because of the
  difficulties in holding a bead on their target, models may not
  use the shooting skills Fast Shot, Rapid Fire and Marksman.
  23
  Steady Air Flow
  It’s windy, but hardened gang fighters are used to such
  difficult conditions and can fight on as normal.
  24
  Fans Down
  The gigantic fans that drive the air around the wind tunnels
  are either switched off or just not working at present.
  Continue your fight as normal.
  25
  Blown Away!
  Winds are high today, making high walkways and gantries
  dangerous. Any model on a gantry or connecting walkway or
  on the top level of any structure must roll equal to or under
  their Strength on a D6 at the beginning of each of their turns
  to remain standing. If the roll is failed, the model is pinned
  and may fall if it is within 1" of the edge of a structure or
  walkway.
  26
  Hang on to Your Hoods!
  Powerful, blustery winds make shooting especially difficult.
  Models shooting at short range suffer an extra -1 to hit penalty
  and models shooting at long range suffer a -2 to hit penalty.
  Because of the difficulties in holding a bead on their target
  models may not use the shooting skills Fast Shot, Rapid Fire
  and Marksman.
  Same old story: a couple of rats and the girls run away screaming...
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  62
  31-36
  Toxic Fog
  The Underhive is an extremely unhealthy place to live. The
  mixture of heavy industry, squalid living conditions and
  fumes from the Sump combine to create clouds of noxious
  fog that drift around the Underhive. As well as being nasty to
  inhale, toxic fog hampers vision, particularly at long range,
  masking fighters behind rolling clouds of vapour.
  Models that don’t have respirators or filter plugs may be
  poisoned by toxic fog and unable to fight. Roll a D6 for each
  model without such protection before set-up: on a 1 the
  model may not fight in the game but is still able to collect
  income, inventory and so forth afterwards.
  31
  Pea Souper
  Billowing clouds of greeny-yellow fog drift through the
  Underhive. Vision range is reduced to a maximum of 10".
  Targets appear and disappear so quickly that models may not
  use the shooting skills Fast Shot, Rapid Fire and Marksman.
  32
  Thick Fog
  Clouds of fog make the going tough. Vision range is reduced
  to a maximum of 16". Targets appear and disappear so quickly
  that models may not use the shooting skills Fast Shot, Rapid
  Fire and Marksman.
  33
  Fight On
  The fog clears for a while enabling you to continue your fight
  as normal.
  34
  Conditions Normal
  The fog has drifted to another section of the Underhive and
  won’t affect your fight.
  35
  Patchy Clouds
  Drifting fog hampers your fight. Vision range is reduced to a
  maximum of 20". Targets appear and disappear so quickly that
  models may not use the shooting skills Fast Shot, Rapid Fire
  and Marksman.
  36
  Charge!
  Both gangs were ready for a scrap but a thick orange fog
  descended a couple of hours ago. Both gangs are about to
  retreat when the fog suddenly lifts. One gang takes advantage
  of the situation by quickly advancing on the enemy.
  Both players’ leaders take a Leadership test on 2D6. The
  player who passes by the most may set up his models again,
  now within 12" of the table edge and automatically gets the
  first turn. Re-roll in the case of a draw. If both players fail their
  tests, they miss their chance to take advantage of the situation
  and proceed with the game as normal.
  41-46
  Bad light
  The Underhive is a dark and dingy place at the best of times,
  and the variable lighting conditions can affect the fighting.
  Models equipped with infra-red goggles and sights are
  unaffected by bad light. Models with photo-visors or contacts
  can see at double the maximum vision ranges in bad light.
  Surrender now! You are already in a sea of goo...
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  63
  53
  Cockroaches
  A carpet of scuttling red cockroaches covers the ground, but
  they don’t affect the fight.
  54
  All Clear
  There’s nothing nasty in the area. Continue the fight.
  55
  Rats
  Hordes of rats charge across the battleground during the
  fight. Rats are particularly troublesome as they get under your
  feet and also give you a nasty bite. This is especially annoying
  when you’re in hand-to-hand combat. Any models in hand-to-
  hand combat must count rolls of 1 and 2 on their Attack dice
  as fumbles. The distraction caused by the rats also means that
  models may not use the shooting skills Fast Shot, Rapid Fire
  and Marksman.
  56
  Big Rats!
  These are mean and nasty. Thankfully there are not as many
  of them as there are of the smaller ones. Each player rolls a D6
  for each of their models. On a roll of 1, the model gets
  attacked by a rat and suffers an automatic flesh wound.
  Reduce the model’s BS and WS by -1 for the duration of the
  game.
  61-66
  SPECIAL conditions
  Some of the most dangerous hive conditions occur quite
  rarely, making them all the more deadly because fighters
  aren’t ready for them.
  61
  Acid Rain
  This isn’t ordinary rain that’s slightly acidic, but pure acid
  falling from a broken silo many levels above. Roll a D6 for any
  models out in the open at the start of the game. On a roll of
  1, the model is burned by acid and must pass a Leadership
  test or go out of action. However, all models that fight on
  valiantly are left with ‘Impressive Scars’ as described in the
  Injuries section of the Necromunda rulebook. The acid rain
  slows to a trickle as the game begins and has no further effect
  on play.
  62
  Methane Gas
  Rotting sewage, fungi and carrion can all create pockets of
  highly explosive methane gas just waiting for a spark (or
  gunshot) to trigger them.
  Any model in cover who shoots and rolls a 1 on their dice to
  hit sets off a gas pocket, which promptly explodes with the
  same effect as a frag grenade centred on the firing model.
  Models out in the open will not trigger gas pockets.
  41
  Pitch Black
  This section of the Underhive is so badly lit that visibility for
  shooting is down to a maximum of 8". Spotting fighters is so
  difficult that models may not use the shooting skills Fast Shot,
  Rapid Fire and Marksman.
  42
  Grim Darkness
  This badly lit area means targets are only visible within 16".
  Spotting fighters is so difficult that models may not use the
  shooting skills Fast Shot, Rapid Fire and Marksman.
  43
  Gloomy
  You can see well enough to fight on as normal.
  44
  Shadowy
  The lighting is poor, but you fight on as normal.
  45
  12 O’clock High
  Extremely bright lights shine from one side of the
  battleground. Models that are facing into this light when they
  shoot will suffer an extra -1 to hit penalty. Roll a D6 to
  randomly determine which is the brightly lit table edge.
  46
  Long Shadows
  Plenty of hiding places amongst the long shadows enables all
  players to run and hide in the same turn.
  51-56
  SWARMS
  The Underhive is prime breeding ground for all sorts of nasty
  life forms: insects and rats do particularly well in the
  squalid conditions. Underhive fighters are used to avoiding
  or killing dangerous creatures most of the time but some
  areas are literally teeming with life. Beastmaster Wyrds
  (which we will cover in a later issue) are never affected by
  Swarms.
  51
  Carrion Bats
  Clouds of carrion bats fly through the area at the start of the
  game. They whirl around fighters’ heads making all but the
  most hardened duck and flinch. Roll a Leadership test for
  each model once they have been set up. If a model fails the
  test it is pinned at the start of the game and may fall if it is
  within 1" of the edge of a structure or walkway.
  52
  Plague of Flies
  There are so many flies swarming through the air and
  crawling over the gangers that it makes it difficult to
  concentrate and see other targets. All models shooting suffer
  a -1 to hit penalty for the whole game. The distraction caused
  by the flies also means that models may not use the shooting
  skills Fast Shot, Rapid Fire and Marksman.
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  64
  63
  Choking Gas
  Noxious, sulphurous clouds of gas rising from waste
  chemicals pervade this area, making fighters choke and
  cough. Both players roll a D6 for each model at the start of the
  game. If the roll beats their Toughness (models with
  respirators or filter plugs get a re-roll) the model has been
  affected by noxious gas and stumbles around in a daze,
  fighting to remain conscious. Roll the Scatter dice to
  determine which way they stumble. Each model affected
  stumbles D3", if they fall they suffer damage as usual. Once
  the bullets start flying, fighters recover their wits sufficiently to
  ignore the gas so it has no further effect once the game is
  underway.
  A Van Saar gang fights the Spyrer Patriarch during a terrible hive quake!
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  65
  64
  Ash Layer
  A thick layer of choking ash and clinker from the forges above
  covers the area. The ash layer counts as difficult ground and
  restricts movement on the tabletop to half its normal value.
  Structures, walkways and gantries are clear so they are
  unaffected.
  65
  Massive Electrical Discharge
  The gigantic hives on Necromunda have to be well protected
  from external weather conditions. Lightning poses a big
  threat as raging storms that can last for weeks circle the hives.
  Huge lightning conductors on the exterior of the hive feed the
  lightning efficiently through the higher levels. Unfortunately,
  this is not always the case in the lower levels of the hive where
  the lightning becomes less controlled and finds its own way
  to ground.
  Roll a D6 for each model once both gangs have set up. On a
  roll of a 1, the model is hit by a huge electrical discharge that
  arcs to him from the nearest bit of metal. Any models affected
  take D6 S6 hits inflicting 1 wound each.
  66
  Hive Quake!
  The Underhive is an unstable place and many gang fighters
  end their careers under piles of falling rubble. After set-up,
  each player rolls a D6 for each of their models. On a roll of a
  1, the model is buried under a pile of rubble and goes out of
  action immediately! What’s more, a hive quake will often
  cause all kinds of secondary problems as it throws up clouds
  of toxic fog, disturbs swarms of creatures, throws up sludge
  flows and so on. Because of this, make a second Treacherous
  Conditions roll once the hive quake itself has been resolved.
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SOURCE: textdata/thevault/Warhammer/40k/Necromunda/03 Necromunda - 2nd Edition (2003)/Senarios/Conditions, special terrain, etc/treacherous_conditions.pdf