Our local hardware store doesn't carry Liquid Nails, which means I've
been using an alternative glue known as "Beats the Nail".
It seems like a fine
substitute at a slightly cheaper price.
One thing to remember with a
product like this is to read the safety label on the tube.
Most of these construction adhesive chemicals give off an "extremely
explosive" vapor that could be a real danger if you're in an enclosed
space. Make sure to keep a window or door open and avoid any sources of
flame or sparks.
From the color of the canister I'm assuming you're using DAP 4000. Looking at it's msds, it contains the solvents n-hexane, toluene, 2-methylpentane and 2-methylpentane. The explosive limits of those solvents are between 1 and 7 percent by volume. Of course you shouldn't light a match under this stuff, but I think you'd have to use a lot of canisters in a sealed room to get to the lower explosive limit. You'd be spaced out from the fumes long before the room explodes around you.
All of these solvents can be harmful to the central nervous system with prolonged exposure. Toluene is a suspected carcinogen and some of the metabolites of hexane are quite toxic. At work we phased out anything containing toluene years ago.
If you breathe enough of these solvents to feel light-headed or dizzy, or if you have a headache the next morning, go and get yourself a filter mask with an activated carbon filter. Generally these kinds of filters are good for about 40 hours of use if kept in a closed container between uses. (Don't bother with a plain old dust mask. It won't do any good against solvents.)
OTOH, the msds also lists titanium dioxide (the most commonly used pigment in the world!) as a possible carcinogen. But this classification only applies to titanium dioxide dust, not when it's part of a putty like this!
The contents of a MSDS are mandated by government (and in the US also state) laws. Personally I find European MSDS's easier to read because they are more standardized and contain less alphabet soup. Usually for mixtures of different substances all the hazards known for all the components are listed, unless the quantities are extremely small. This sometimes has the unfortunate effect of overstating the dangers, but this is considered better than understating the risks. (This is at least partly because for a lot of chemicals the effects of human exposure are basically unknown.)
Luckily an effort called GHS is underway to harmonize labels and classification of chemicals worldwide. Currently there is a hodgepodge of rules and labeling requirements. GHS will make it simpler to recognize the effects and risks of chemicals.
Fortunately the pictograms that have been a cornerstone of hazard identification in the EU have been adapted (in a somewhat changed form) for GHS as well. So from 2015 forward you should be able to recognize e.g. flammable resp. toxic substances from the following labels;
People living near water should be really careful with aquatic pollutants;
(These are just some examples.) When using labeled chamicals always read the directions.