I generally agree with Jerry here.

The term "myco" means fungal, and a "mycotoxin" is a poison that covers the surface of spores produced by certain fungii. Fungal spores are so tiny, that initially there was considerable debate amongst medical professionals as to whether the amount of mycotoxins that would be ingested by inhaling the spores of those molds would be enough to make a person sick. And, as a result of studies, they've found that some people are more sensitive to myco toxins than others. In general, the worst effect of inhaling mycotoxin coated spores is that a person gets much the same symptoms as the common cold; a general feeling of being unwell, runny nose, cough and headaches. Most people never even feel sick from inhaling mycotoxins.

But, what about the advertisements from contractors specializing in mold removal that say that mycotoxins can be deadly? The truth is that ingesting huge amounts of mycotoxins CAN cause people to get very sick, or have failure of their major organs (like the liver) and even die, but those cases are not the result of inhaling mold spores. Those cases are the result of people eating the wrong kind of mushrooms.

The mold removal business today is driven largely by fear and hypochondria. People get older and gain weight, and they look for a reason to explain why they're not a active and healthy as they were, and often they blame BLACK MOLD!!! So, an entire cottage industry has bloomed removing mold from people's houses.

In actuality, if you simply remove the source of water that mold needs to survive, you'll get rid of the mold as well. Often, this isn't practical. For a house with a concrete basement that wasn't properly water proofed on the exterior, moisture will migrate into the basement walls and cause mold to grow inside those walls. That's exactly what happened in the house I grew up in, and I never felt sick despite my being the only one in our family who had a bedroom in that basement and slept down there every night from the time I was about 12 until I was about 16.

If you want to kill mold spores, probably the most effective way without making a mess by splashing Lysol around is to rent a machine called an "Ozone Generator" or simply "Ozone Machine". Just phone around to the places listed under "Janitorial Equipment & Supplies" in your yellow pages phone directory, and many of those places will either rent them or know who does.

Ozone, chemically O3 is an "oxidizing bleach", just like Javex or Chlorox Bleach, or hydrogen peroxide. Ozone (O3), bleach (NaOCl) and hydrogen peroxide (HOOH) all spontaneously break down to form more stable molecule, and in the process spit out a lone oxygen atom.

How to say this politely? Lone oxygen atoms are the horny drunken sailors of the chemical world. They will react with anything that's unstable enough to react with them, and that generally means things that will break down by themselves given time. And that, in turn, means large organic molecules. It is large organic molecules gat give rise to smells and tastes in the foods we eat. Large organic molecules called "dyes" are famous for allowing us to change the colour of fabrics. We have large organic molecules in our hair that determines what colour our hair is.

Oxydizing bleaches spontaneously break down to form oxygen, salt water or water and spit out a lone oxygen atom when they do. That oxygen atom reacts with large organic molecules breaking them into pieces. When that happens, the resulting pieces of molecules no longer absorb light, or affect the sensors in our noses or on our tongues the same way the original molecule did. So, when you bleach a T-shirt, the dye is still on the shirt, but it's been broken into small pieces that don't absorb light the way the original molecules of dye did. Ditto for smells and tastes. When a person dies in a house, and the body isn't discovered until the neighbors start to complain about the stench coming from the house, it's an ozone machine that's used to break down all the organic molecules in the air before the house goes up for sale (if that's what the beneficiaries of the will want).

So, if you want to kill anything in the duct work of the house, instead of splashing bleach around, a smarter move would be to set up an ozone machine and have the furnace circulate ozone through the ductwork.

Ozone is very unstable. Within 2 or 3 hours of shutting the ozone machine off, all of the ozone will have broken down to form oxygen, and the lone oxygen atoms will have reacted with whatever large organic molecules they came into contact with. NOTHING can survive it's constituent molecules being broken up into pieces, not even mold or mold spores.

But, ozone molecules will attack all large organic molecules they encounter. So, try and constrain the ozone to the ducts as much as possible. Ozone will lighten the colour of dyed carpets and dyed draperies. Cellulose is a large organic molecule made of sugar molecules stacked up like bricks in a wall. If you leave a cellulose sponge in bleach overnight, by morning the sponge will be mush. The cellulose molecules are still there, but they've been broken up into small pieces that no longer have any strength. So, when you squeeze that cellulose sponge, you get a ball of much that doesn't return to it's original shape.

Anyhow, by keeping your duct work dry, any spores that are inside your ducts will eventually die. The mycotoxins, if any, on those spores aren't generally enough to make people anything more ill than they would be if they had a cold. And, once those people are no longer inhaling mycotoxin coated spores, their health returns to normal.

So, I'd say that if you wanted to sterilize your ducts and kill any mold or spores in them, the way to go would be to use ozone, and keep everyone out of the house while the ozone machine is generating ozone. And, as Jerry said, humans have been exposed to mycotoxins for thousands of generations as we evolved from apes, and we're pretty well used to mycotoxins. So, when people inhale mycotoxins, those that do get sick don't get any sicker than they would from a cold. The companies that make a business out of removing mold from homes survive largely on fear of the unknown and hypochondria.

Hope this helps.