Notes

Borax
statement 1.
Borax, sodium tetraborate decahydrate, according to one study, is not acutely toxic. Its LD50 (median lethal dose) score is tested at 2.66 g/kg in rats, meaning that a significant dose of the chemical is needed to cause severe symptoms or death. The lethal dose is not necessarily the same for humans.

statement 2.
Borax, which is also known as Boric Acid and is sold under the brand name "20 Mule Team," is often touted as safe and natural. While it is a naturally occurring mineral, that doesn't mean it is without dangers.

Borax is often recommended as a "safe" pesticide, fungicide and cleaner, but it is officially classified as a poison. Government sites recommend that people who work with Borax use gloves and handle it with caution. Studies have linked it to reproductive problems in some lab animals, as well as a host of serious disorders at higher levels.

statement 3.
Borax (Sodium Tetraborate) is not safe for consumption, and should therefore be handled and used carefully so as to avoid ingestion, although in the quantities actually present in slime it should not cause any concern.

Guargum (in barrel o slimes)
Guar gum is not hazardous when eaten, however it can be used as a laxative, so it would probably be unwise to consume large quantities.

PVA Glue (Polyvinyl acetates)
PVA (Polyvinyl acetates) are probably the most common adhesive on the market. They come in a variety of formulas, all ever so slightly different, and specific to what they are designed to glue. Here are some tips for using Polyvinyl acetates.

All PVAs are designed to work on porous materials only
PVAs are water based, and clean up with warm soapy water.
PVA is only toxic to ingest, it does not emit any harmful fumes, and is not hazardous to touch
PVA sets best in good air circulation, at room temperature.
PVAs need pressure to adhere, see our info on clamping.
Most PVAs are not water proof. The yellow PVAs have a higher moisture resistance than the white ones, but neither are completely water proof.
Never allow your PVAs to freeze. This breaks down the polymers and your glue will be rendered useless!
Yellow PVAs have a shorter shelf life than white PVAs.
Be wary of over priced PVAs that claim to be for a specific use. There is very little difference from one PVA to the other, and nothing that should increase the cost.
Although PVA is not a gap filler, in some cases you can add sawdust to it to increase its gap filling ability.

Borax slime statement
Borax slime:

Borax is a poisonous chemical which is available from supermarkets. Polyvinyl alcohol is a hazardous, flammable chemical generally not available for household use and needs to be purchased from scientific suppliers. Eye protection and gloves need to be worn at all times when handling both these chemicals.

Once these chemicals are reacted the slime produced is washed with water and is then considered non - hazardous. The slime produced should not be ingested. Food colour is usually added and this may stain skin, clothing and upholstery. The slime can only be stored for a short period of time usually in a zip lock bag in the fridge as it has the potential to become mouldy after handling. Slime bought commercially generally contains preservatives.