Goretex, generally consists of three chemicals.
The outer (wear resistant part) is simply nylon or polyester.
This is typically non-hazardous and can be disposed as any other plastic (bearing in mind the long periods of time this is likely going to take to decompose)
This is the "Gore-tex layer". Goretex itself is simply a Polyurethane/PTFE polymer based plastic. Fully reacted (as in Goretex) polyurethane polymer is chemically inert. PTFE does generate potentially noxious gases at temperatures over 250C, So don't burn it! Again this is typically deemed safe though (as above) it takes a long time to decompose.
The production of PTFE also involves the chemical PFOA . This is highly toxic. Though all of this chemical is removed by the final product (i.e. the Goretex itself is not toxic) this chemical (used in the production of Goretex/PTFE) is potentially long lived in the environment. Several legal actions have been successful against DuPont (though no liabillity was admitted) against the release of this chemical into water course.
Goretex is also coated with Durable water repellent coating. This is a Fluoropolymer. Again this is typically safe. If large amounts of Fluoropolymer's get into water they can cause issues with fish, aquatic animals, etc. So again this is an environmentally sensitive product.
- Goretex is safe for humans, all the chemicals involved are generally inert and have been passed as safe by every government agency in the world
- When Goretex is disposed of it can cause environmental damage
- The production of the chemicals in Goretex are themselves
environmentally sensitive, the production creates pollution and uses
oil as the main ingredient.
Is this true for other breathable membranes as well?
Typically yes, they all use variations on the theme above
Are there membranes that are free from toxic substances?
Yes plenty! Wool, wax jackets, etc. Are they as effective and breathable, typically no, especially when your talking about breathabillity.