Footwear waterproofing technology has just taken a giant step forward - but we're wary of the implications.

Shoe manufacturers Hi-Tec have just unveiled a form of chemical treatment that can be applied to any surface to render it waterproof. The significant word is surface: unlike traditional waterproofing techniques which rely on layers to trap moisture, the new "ion-mask" technology coats the outside of shoes with a material that repels water, making it bead and run away before it can be absorbed. Since porous surfaces can be treated in this way, a shoe can be waterproof and fully breathable.

Sounds great - but in the absence of hard facts, here's a few questions we have:

Ion-mask uses a chemical that is "based on flourine". There's a worryingly large amount of toxic substances that are also based on flourine, such as the extremely corrosive hydrofluoric acid (pdf). What's the chemical?

How quickly does this flourine-based compound biodegrade in the environment, and into what? Furthermore, how does it affect the way the material it's coating biodegrades?

If this is an inert, durable substance that does no harm, it's a winner - as it's replacing traditional waterproofing chemicals like Durable Water Repellents (DWRs), some of which decay into the surfactant PFOA, a suspected carcinogen. (And DWRs wash off waterproof clothing, which is why you need to renew them periodically).

Hi-Tec claim the environmental impact of using ion-mask is "small"...and we're keen to see if this holds water.

Image: Jenny Downing