In the missile silo near Abilene there are no snakes inside, no rats, mostly nothing at all alive inside due to no sunlight. Only light inside is artifical and it is only on for a few days a month so nothing lives inside. Any critters that sneak in when there are divers die of starvation. But it is Texas, there are shakes outside. The poor vis is due to divers stirring up the insulation, sand, dirt and dust on the bottom and sides. The owner has the water tested regularly. Asbestos is not a hazard when it is wet but I believe the place has been remediated. Diving is safe other then the usual hazards associated with diving. Carrying the gear up and down the stairs is quite a challenge but do able.
The guy that worked there and was on the board no longer works there.
Joe