Recently, two incidents in Vietnam have highlighted the potential dangers of toxic gases being released during the shoe manufacturing process. In the first incident, at least 110 people began vomiting and passing out, with several being hospitalized. Both incidents occurred in factories using the same equipment and shoemaking materials. While the accidents are currently under investigation, the symptoms are consistent with gaseous poisoning from VOCs.
Volatile Organic Compounds
VOCs are organic chemical compounds that easily evaporate under normal indoor atmospheric conditions. The higher the volatility (lower the boiling point), the more likely the compound will be emitted from a product or surface into the air. They have been linked to a range of negative effects, including headaches, eye and throat irritation, nausea, dizziness and drowsiness, and some, such as benzene, can be carcinogenic.i
Many countries regulate VOCs. For example, the European Union (EU), which defines VOC as "any organic compound having an initial boiling point less than or equal to 250 °C (482 °F) measured at a standard atmospheric pressure of 101.3 kPa,” has Regulation (EU) 1907/2006 (REACH), Directive 1999/13/EC (The VOC Solvents Emissions Directive) and various regulations and standards for air quality and emissions.
VOCs also appear on industry restricted substance lists (RSLs) from organizations like the Apparel and Footwear International RSL Management Group (AFIRM) or American Apparel and Footwear Association (AAFA), and on manufacturing restricted substance list (MRSL), such as Zero Discharge of Hazardous Chemicals (ZDHC).
For footwear manufacturers it is important to note China has recently begun introducing restrictions on VOCs in several industries and this will impact production.ii
VOCs in Shoe Manufacturing
VOCs are introduced into the shoe manufacturing process at three main points:
- Material processing e.g. leather tanning – degreasers, synthetic tanning agents and solvent-based leather finishing products – and the manufacturing of synthetic materials such as PU leather and PVC, etc.
- Assembly – solvent-based glues
- Finishing – substances used during cleaning, marking, polishing and dressing
Shoes will come into contact with several VOCs during manufacturing. A study of 490 footwear facilities in the Chinese province of Zhejiang produced an extensive list of VOCs, including methyl ethyl ketone (MEK), toluene, acetone, cyclohexanone, ethyl acetate, xylene, dichloromethane, cyclohexane, dimethyl carbonate, vinyl acetate. Other ingredients included benzene, chloroform, hexane, formaldehyde and acetonitrile.iii
Bad for Business
VOC present a threat to workers in factories, where gases can build up during manufacture, and to other workers along the supply chain. In the Netherlands, shipping containers holding shoes have been held at ports because the odor and gases contravened local laws. In both cases, the shipments were significantly delayed while the containers were degassed. If the gases hadn’t been identified, the effects could have been similar to those in the Vietnam factories.
Part of the problem stems from the fact VOC gases accumulate over time and may not, therefore, be readily identified until it is too late. In the case of the Vietnam factory workers, this was when they became ill. For the shipping containers, it was when the consignment reached dock. In both instances, the human consequences can be acute, and the impact on the businesses severe.
Today’s global markets require speed and efficiency. Delays or rejection at the border slows down or impedes the supply chain. While companies may not currently be able to completely phase out the use of VOCs in shoe manufacturing, they do need to ensure that VOC application is controlled and minimized. If products are rejected or delayed because of VOC application, the financial impact on the manufacturer or supplier can be severe.
Finding a Better Way
SGS offers a comprehensive range of solutions to help footwear manufacturers deliver safe, compliant products to their target market. Taking a holistic approach to VOCs, we can help brands implement multi-year VOC reductions plans, undertake root cause analysis to identify where VOCs are entering the value chain, and even support brands when consignments are held at borders. From processing, through manufacturing and shipping, SGS has the expertise to help footwear manufacturers meet their obligations regarding VOCs.
For more information, please contact:
Eric Wang, PhD
Consumer and Retail
Global SL Chemical Services and Innovation
Phone: +86 (0)21 6115 6893
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iii Pollution Characteristics and Emission Coefficient of Volatile Organic Compounds from Shoe-making Industry in Zhejiang Province. Zhirong Xu, Yi Yao, Weidan Cai, Yan Li, Mingzhu Xu, Zheming Wang. 10, s.l. : Environmental Science (in Chinese), 2016, Vol. 37. 3702-3707