Footwear Ecology Question 5
Does the brand (company) have a clear and effective policy to minimize environmental pollution of chromium and other harmful substances from leather tanning processes, e.g. by waste water treatment or by vegetable tanning?
NL: Heeft het merk een effectief beleid voor het looien van leer, om milieuverontreiniging door chroom en andere schadelijke chemicaliën te beperken, bijvoorbeeld door waterzuivering of vegetaal looien?
DE: Setzt der Markenhersteller Maßnahmen um, um Umwelt- und Gesundheitsschäden durch den Gebrauch von Chrom und anderen umwelt- und gesundheitsschädlichen Substanzen beim Gerben von Leder zu vermeiden?
Tanning is the process of treating skins of animals to produce leather, which is more durable and less susceptible to decomposition. Chromium is the most commonly used agent in leather tanning processes. The chrome tanning process is relatively cheap and quick and gives leather the required characteristics. There are however several problems related to chromium tanning. Here it should first be noted that chromium is a transition metal that can exist in different oxidation states each with distinctive properties and toxicity:
1. Trivalent chromium (Cr III) occurs naturally in the environment. Chromium III is considered safe to use and is non-hazardous . It is used in the leather industry for tanning.
2. Hexavalent chromium (Cr VI) is the hazardous, carcinogen form. It can be formed when trivalent chromium is oxidised. This usually occurs in the presence of oxygen combined with other factors, such as extremes in pH or temperature .
Although the leather tanning agent Chromium III is considered safe, the use for leather is still not desirable. Chromium III as used in tanning process could oxidise to Chromium VI during or after production, e.g. due to uncontrolled temperatures and pH levels. This may pollute the local environment, cause harm to the leather workers, or can end up in footwear. Further, chromium tanned leather contains a considerable chromium content. Chromium is persistent: it cannot be broken down and will always be present in some form within the environment. Incineration of old shoes can again cause Cr III to oxidise into Cr VI. Incineration, composting and gasification will not eliminate chromium; this prevents ecological recycling of materials .
Additionally, some people are allergic to Chromium III. This is a reason for Volvo to ban chromium tanned leather from their cars. There are also national legislation prohibiting chromium in baby and children leather products .
Alternatives and (partial) solutions
• Vegetable tanning, here natural materials are used, such as bark and leaves of plants. The environmental advantage of vegetable tanning is that no chromium is used and does not end up in leather and consequently, the environment. However promising, the vegetable tanning process generally takes more time and may consume considerable more energy and water. Overall environmental benefits of vegetable tanning versus chromium tanning is therefore debated, a reason for Timberland not to prioritize this material as environmentally friendly.
• Tanning processes using other agents than chromium (see e.g. options indicated here: , .
Brands are given the 'Yes' to this question when at least 50% of the used leather is tanned without Chromium.
• Waste water treatment and strictly controlled tanning processes, in order to prevent Chromium III to oxidise into Chromium VI and to limit the chromium released into the environment through waste water effluent. Please note that this solution only applies to the production stages, while chromium will still be in the leather and may cause problems in the disposal stage (incineration). One of the leading initiatives in environmentally responsible tanning is the rating system of the Leather Working Group (LWG) where tanneries are awarded a Bronze, Silver or Gold rating.
Brands are given the 'Yes' to this question when at least 90% of the leather comes from at least LWG Silver certified tanneries (best practice by Timberland and Nike), or at least 90% from tanneries with a comparable certification or comparable environmental performances.
• [Brand] reports that [%] of the used leather is tanned without the use of chromium but with the use of [vegetable / other technology] instead.
• [Brand] reports that [%] of the used leather comes from tanneries with at least a [bronze/silver/gold certification according to the Environmental Working Group / other certification].
• [Brand] reports that [%] of the used leather comes from tanneries with clear environmental performances that include waste water treatment and effluent values [..](see link/page).
• [Brand] does not make use of leather for its products at all (see link/page).
• [Brand] explicitly reports about not having a policy to limit chromium and other harmful substances pollution caused by leather tanning processes, for the reason that [..](see link/page).
• [Brand] reports a policy to limit the [pollution of chromium / environmental pollution] such as [..], but the brand does not clearly describe any [concrete performance / percentage on the total use of leather] (see link/page). The brand is therefore not clear about the scale and impact of this policy.
• [Brand] does not openly communicate a policy to limit chromium and other harmful substances pollution caused by leather tanning processes. Sustainability information should be easily accessible for consumers to make responsible choices.