Open letter - Chrome tanning maligned

The open letter

Since 2006 The Blacksmith Institute and Green Cross have been listing what they consider to be the world’s worst pollutants and polluters. They continually give wrong and damaging information about chromium and tanneries. The recent 2011 Report continues the misinformation and should be withdrawn.

Among many issues, the reports do not adequately differentiate between Cr III and Cr VI. Cr III, as Basic Chrome Sulphate (BCS), is used to tan leather and is not toxic or hazardous. Cr VI can be toxic and carcinogenic although low levels can be tolerated. Several Blacksmith reports refer to Cr VI pollution in India from the manufacture of BSC from chromite. This was a problem in many countries in the past, but has now largely been addressed. Importantly, these were chemical factory problems, not tannery problems.

Leather has been chrome tanned throughout the world for more than 100 years and all the wastes have been distributed into the environment with few problems. Until the 1970s, most tanneries discharged waste to sewer, water or land with little or no treatment. Now many tanneries are reusing Cr III, minimising waste and meeting discharge limits that are often far more stringent than necessary for protection of health and the environment.

Greenpeace in Argentina are now campaigning for tanneries to adopt a clean production program having a goal of no chromium in the effluents and waste. This goal cannot be achieved, is unnecessary, and is being contested. The world must have scientifically based restrictions and Greenpeace must review the science and their requirements.

A number of companies using leather, including Nike, Adidas and Puma, have recently announced that they are working toward a goal of zero discharge of hazardous chemicals for all products in their supply chain by 2020. It is unrealistic, unreasonable and unnecessary to require zero discharge. Also, any list of hazardous chemicals must be scientifically justified.

The real environmental effects of using chromium to tan leather should be understood because, for the foreseeable future, chromium will be crucial for the world leather industry. Cr III is not hazardous but to be sustainable, waste and discharge must be minimised to reasonable levels.

The IULTCS issued a press release ‘Inaccurate Portrayal of the Leather Manufacturing Industry by the Blacksmith Institute’ on December 2, 2011. Blacksmith Institute responded to IULTCS on December 15, 2011. This response referenced two papers to support their views about Cr III. However, both studies referenced by Blacksmith actually support the considerable evidence that Cr III in soils and tannery sludges is inert: conversion to Cr VI is not a problem. Neither reference supports the Blacksmith claim that tannery waste becomes hazardous nor that trivalent chromium easily oxidizes to become hexavalent chromium upon disposal.

Dr Catherine Money has written a comprehensive, referenced, Open Letter to Blacksmith, Green Cross and Greenpeace: ‘Chrome Tanning Maligned’. The Open Letter was completed on December 6, 2011. On December 16, 2011 she wrote a Postscript to the Open Letter which comments on the Blacksmith Institute Response to IULTCS. Both the full Open Letter and the Postscript will be published in the January/February 2012 edition of Leather International magazine.