The big difference is the long-term hazard to your health if you breathe in dry dust containing asbestos fibers. What makes it difficult to minimize this hazard is that demolition is generally a pretty dusty business, and that the fibers are microscopic and so light that they can hang in the air long after other components of the dust have settled and been swept up. There are a couple of basic considerations that apply to every asbestos-abatement project: keep it wet, keep it in the smallest area possible, avoid raising dust, protect all workers on the project from breathing the dust. Special tools and methods to suit each of the types of asbestos-containing material (ACM) you're likely to encounter in your home. If you're hiring a professional abatement contractor, it is still good for you to be knowledgeable about these considerations so you can evaluate proposals and supervise the work.

Keep it wet:

How specialized you need to get depends on the size of the work area where you need to remove asbestos, and to some extent on how friable the asbestos-containing material is when you start.

For outdoor, fairly rigid materials such as roofing or siding, as long as it is in good condition and you are a little careful, you do not need to do more than surface wetting right where you are working. For a large area inside, such as sprayed-on or troweled-on acoustic or insulation materials on ceilings and walls, you'll be glad to have a tank sprayer that holds two or three gallons at a time. It needs to spray by pumping it, not by electricity, because the whole area will be very wet. You also need to be able to control it pretty well, because you do not want to wet material too far ahead of where you're working, or the material will fall of its own weight and you will have the air filled with dust. You need to work carefully and wet the material all the way through to the wallboard or other underlayment before you touch it. This will take some experimentation to find how many times to spray it and how long to wait between applications of water. The size of the sprayer is simply to avoid having to go back out of the work area to refill before you have finished.

A professional contractor may even bring in a mist machine to keep the air damp throughout the work. This is meant to capture any stray fibers and make them heavy enough to sink to the floor for cleanup when the job is done.

For a smaller area, including when you're collecting samples for testing, you can use a household spray bottle such as you might use to wash windows or mist plants.

If the material is basically waterproof, such as vinyl flooring, or has been encapsulated with a waterproof coating, your problem is to wet the underside just as quickly as you lift it up, even if it is only to keep the dust down where you're forced to tear and break the material. It's more often the backing or underlayment of vinyl flooring that contains asbestos, or even the mastic that's holding it down.

Any sprayer mechanism will be more useful if you can adjust the fineness of the mist it produces.

Add liquid dishwashing detergent to the water in your sprayer, a few drops in your handheld bottle, a cup of soap in a five-gallon tank. This "amended water" will make it easier to get the asbestos-containing material wet through and will take longer to evaporate and raise the dust hazard again.

Keep it in the smallest area possible:

If your project is small and well contained, such as asbestos-containing insulation on pipes, there are special bags available with gloves built into the sides of them. You put tools inside the bag (such as in the palm of a glove, pulled to the outside) and seal the bag over the pipe and its asbestos blanket (already wet, but you should also have additional water in the bag to use on cut edges and for cleaning the pipe after the asbestos is off). You need only small tools for this kind of job, though you will not be able to see what you're doing very well if at all. When you get the blanket off, lower it gently into the hanging bottom of the bag. Clean the pipe thoroughly with a wet rag, then crimp the bag tightly in the middle while you remove it from the pipe and seal in the asbestos debris (including the rags you have used) as quickly as possible.

A whole room where a wall or the ceiling is covered with asbestos-containing material has to have every surface other than the ACM sealed under thick polyethylene plastic sheeting. You'll need enough sheeting that's two or three mils thick to cover the walls one and a half times (you'll need a wide overlap on every seam). For the floor you need sheeting six mils thick to cover three times. You also need sheeting to cover every window or door twice, and unless there's an exit to the outside air, you need to build an "air lock" in an adjacent hallway or out into the next room for workers to make the transition between the work area and the "clean" part of the house.

All of this plastic sheeting, plus ventilation registers and disposal bags, will be sealed with duct tape. You can hardly overestimate the amount you'll need, and the last thing you want to do is to skimp on it. Special disposal bags are made for asbestos-contaminated waste. They're thick polyethylene, much tougher than ordinary garbage bags, transparent, and preprinted with the label required by the Environmental Protection Agency. They can be filled only far enough that you leave a good long twisted "gooseneck" to fold over and seal to the side of the bag with tape, and every bag has to be doubled. The closed bags go out and into their transport as soon as possible, and the transport takes them to the landfill at least every day. You do not want this stuff sitting around waiting for an accident.

Again for full protection, a contractor may bring in a "negative-pressure" system of fans to blow air out of the work area through a high-efficiency particulate air (HEPA) filter and constantly create lower air pressure around the asbestos than outside so that the HEPA filter is the only way that air can get out.

Avoid raising dust:

Do not ever scrape, chip, or sand asbestos-containing material. Always use slow, smooth pressure to peel the ACM off of other material or to cut it away from the neighboring section.

Remove ACM of any kind in the largest pieces possible. For instance, peel ceiling or wall textured materials from the underlying surface using the widest wallboard taping or "putty" knives you can get, usually four to eight inches wide. Catch the material as close to the ceiling or wall as you can, using a dust pan. From the dust pan you can slide it gently into the waste bag.

Do not use power tools unless it's absolutely necessary. (Most materials hard enough to require power tools, such as cement pipe, also encapsulate their asbestos fibers very firmly, but you should still take care not to raise dust).For cutting off blanket-type pipe insulation, even if you have the pipe encased in a glove bag, your best tool is a small wire knife that you can pull firmly through the material against the pipe after wetting and peeling back the canvas covering. You may also need pliers and wrenches for removing metal bands that may hold the insulation on.

Do whatever you can to soften the asbestos-containing material before you begin to pry it off its substrate or underlayment. Wetting it is the best method unless it's something water-resistant like vinyl flooring. Even if you can't soften it, try to bend it up in large pieces rather than smash it into small bits, because every edge can release fibers. Work slowly and steadily instead of with high-powered force. Go straight across an area once for the bulk of the material, and go back to get the bits still clinging (after you rewet them) in a second pass. Do not scrape back and forth while the big piece is hanging over you.

Keep any dust that is raised out of everyone's lungs:

Everyone working on the project should at all times wear a half-mask, two cylinder respirator with purple-coded high-efficiency particulate air (HEPA) filters.

Goggles, an impermeable coverall with hood, rubber (not latex) gloves, and molded boots complete the costume to keep dust away from each worker's skin. Everything gets removed every time a worker leaves the work area, and everything but the respirator housing, the goggles, and perhaps the boots gets disposed of each time as asbestos waste.

When the job is done, you will need additional rags (lots of them) because they become hazardous waste; you cannot rinse and reuse and water to wipe down whatever surface was under the asbestos-containing material, every ladder or other tool you are retaining (but don't be stingy; if at all possible, throw it out). You need to wipe it both before and after removing the plastic.

A contractor may give the area a last going-over with a vacuum cleaner that also has a HEPA filter rated for asbestos.

Take durable tools, such as ladders, outside immediately and give them a thorough, hard spray with the hose as far from people as you can get, and leave them outside for at least a day after they've dried.

If the asbestos was on a surface that's even slightly porous -wallboard, say, as opposed to metal pipe - spray that surface with latex paint, shellac, or another liquid that will dry with a hard surface, to encapsulate any asbestos fibers that may have escaped efforts to remove them.

One last sweeping word on tools and supplies: think the project clear through before you begin. If there seems the least possibility you might need something later, leave it in your "air lock" where a protected transitional worker can hand it in. Take in a ladder tall enough to let you reach the asbestos-containing material comfortably and let you work easily. The coverall will be uncomfortable enough, and the gloves and boots will make you clumsy. You cannot eat or drink while you're working on asbestos abatement; wait until you leave the work area and have showered thoroughly.