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a brief history
selection criteria for the tyre lists
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General

More than 60 000 tons of tyres are consumed in Sweden each year and across the EU the figure is around 2.1 million tons. A large proportion of the tyre tread (10 000 tons annually in Sweden) ends up in the air or in roadside ditches as it is worn away on the roads.

By far the greatest environmental and health risk from car tyres comes from the high aromatic oils (HA oils) in the rubber mixture. HA oils are to be found in a proportion of up to 20% which means that there is up to one litre of HA oils in each car tyre.

HA oils are hazardous waste that are produced when lubricant base stocks are refined in the lubricant production process. Amongst other things HA oils contain high levels of polycyclic aromatic compounds (PCAs) and are classified as toxic because of their carcinogenic nature. They also pose a danger to water-based organisms because many of the PCAs present are poisonous and biodegrade very slowly and bioaccumulate.

Each year 250 000 tons HA oils are used in the tyre and rubber industry in Europe. It is estimated that 30 - 40 000 tons of HA oils are dispersed each year through tyre wear, of which 1000 tons are released in Sweden.

HA oils are not chemically bound to the rubber. They tend to leach from the mixture and migrate into the surrounding environment. Studies recently undertaken at the Zoological Institute at Gothenburg University showed that fish exposed to tyre pieces in running water activate their very specific defence against polycyclic aromatic compounds.

A new study from the Institute of Applied Environmental Research at Stockholm University found a high acute toxicity to water-dwelling organisms in the waters around Stockholm. A strong effect has been pointed out for non-migratory fish in the Stockholm area, where the toxicity is due mostly to PCAs. A significant proportion of these polyaromatics can originate from tyre wear.

It is not only in the use of tyres that HA oils pose a threat. The carcinogenic effects may constitute a risk in the work environment in tyre manufacturing plants. HA oils also cause problems at the end of the tyre's useful life because the possibilities for recycling are limited. This can have serious consequences, for example, if piles of old tyres are set on fire.

There are few chemicals that - at the same time - constitute such a high danger to health and environment, are used in such quantities and are dispersed as widely in the environment, as HA oil in tyres. "Rivals" to this are fuels and maybe heavy fuel oils used in shipping.


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A brief history

The issue of HA oils in tyres was first raised in a report from the Swedish Chemicals Inspectorate called 'Nya hjulspår' (Ahlbom, Duus, 1994. KEMI report 6/94). The report received significant attention from the international tyre industry.

In a hearing at the Swedish Chemicals Inspectorate in 1995, BLIC (the European Association of the Rubber Industry) claimed that the problem was not as great as was presented in the report. They also claimed that it was technically very difficult to replace HA oils and that the safety performance of tyres could be at stake. The Inspectorate maintained, however, that HA oils should be phased out and BLIC began work to investigate the alternatives.

Within 6 months, the first retreaded HA oil-free tyres were presented by Swedish retreaders - with Anderstorps Gummiindustrier (AGI) leading the way. AGI's winter tyres received very good results in technical tests undertaken by the Swedish motor magazine "Teknikens Värld".

The retreading industry has now undergone a comprehensive transformation and nowadays almost all retreaded tyres sold in Sweden are free from HA oils in the treads. The Swedish retreading industry is internationally respected and the proportion of total tyre sales that are retreads is the highest in the world. A number of brands of retreaded summer tyres have now also received good test results - even with regards to wet weather grip. Some brands have even been awarded the Nordic Swan ecolabel.

In 1997, the Swedish Gislaved tyre plant (within the Continental Group) presented the first new winter tyres without HA oils in the tread. In 1998, the tyres were hailed as 'tyre of the year' by the motor magazine "Teknikens Värld". This was 'despite' them being free from HA oils. The judgement resulted in a breakthrough for HA oil-free winter tyres and several of the major international manufacturers felt forced to follow the trend.

At the same time, BLIC announced the European rubber industry's aim to try to replace HA oils in tyres wherever alternative resources were available. However, they did point out difficulties with regards to wet weather grip for summer tyres amongst other things.

One issue was that it was not possible to check whether a tyre contained HA oils or not. The only source of information for purchasers was the manufacturers' information. The Swedish National Testing and Research Institute, who have great experience in analysis of polyaromatics in oils, developed a method for testing polyaromatic compounds in vulcanised rubber.

In autumn 2000, Grön Kemi and the Swedish insurance company Folksam compiled the first Swedish list of winter tyres without HA oils. Spot checks on a large number of winter tyres showed that many of the leading manufacturers had tyres on the market that were free from HA oils. In particular, the majority of newly launched models were free from these oils.

Updates to the tyre list over the last years show that the majority of winter tyres on the Swedish market are free from HA oils in the treads (now approximately 90%). Even products from major manufacturers in Japan and Korea are on the list. The main users of the list have been large purchasers of tyres; for example Västra Götalandsregionen, Folksam and many local authorities.

Approximately half of the tyres purchased in Sweden are for trucks and buses. Fortunately, the problem with HA oils is not as great for these vehicles as for cars. The concentrations of HA oils are lower than in car tyres and are easier to replace due to a slightly different rubber blend. The issue of replacing HA oils has been kept high on the agenda for the last few years by the truck industry, mainly driven by a company closely linked to the haulage branch called TRB Miljö. Nowadays HA oils have been replaced in a large proportion of these tyres.

Once the tyre plant in Gislaved started work on replacing the oils in winter tyres in 1997, the production process was soon modified so that the entire factory was free from HA oils - not just in the tyre tread, and even in summer tyres. Unfortunately, the German owners of the plant, Continental, made the decision in 2002 to close this plant despite it being the most advanced plant in the world regarding health- and environmentally enhanced tyres.

Early in 2002, Nokian Tyres in Finland presented a new summer tyre manufactured without any HA oils in the tread. The company's aim is to have all HA oils out of production by the end of year 2004.

The Grön Kemi project has also produced an updated list of summer tyres without HA oils in the tread (once again in collaboration with Folksam). Spot checks have been used to confirm that retreaded summer tyres, Nokians new tyre model and the remaining tyres produced at the Gislaved plant are free from HA oils in the tread.

At this stage there are both winter and summer tyres - free from HA oil - that has been appointed "test winners" in the different Swedish motor magazines. The technical features in these cases, like wet grip for example, now equal or outnumber the traditional tyres.

This summer tyre list, including information on Nokians efforts, the closure of the Gislaved plant and summarising the situation regarding summer tyres, lead to significant interest from the mass media. The Swedish Minister of Environment, Lena Sommestad, became aware of the problem and commissioned the Swedish Chemicals Inspectorate to investigate what conditions would be necessary for a Swedish ban on the use of HA oils in car tyres.

Sweden and Germany have also initiated the issue of HA oils in tyres to the EU Commission. A proposal for a ban on HA oils in tyres put on the market in the whole European Union is now put forward by the Commission. Hopefully this proposal will reach the European Parliament during the spring 2005.

The 9th of June the EU Parliament decided to ban all use of the carcinogenic and toxic HA-oil in tyres. The ban will come into force from the 1st of January 2010 and comprises all tyres sold within the EU.

 
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Selection criteria for the tyre lists

An oil is classified as toxic and carcinogenic if the concentration of PAHs in an extraction with DMSO is greater than 3% using measurement method IP346/86. This is defined by the EU classification and labelling criteria (Directive 67/548/-EEC with appendums). However, such a method is difficult to apply to tyres because the analysis method is not applicable to vulcanised rubber.

However, the Swedish National Testing and Research Institute (SP) in Borås has developed a method to determine which types of oil there are in a vulcanised rubber tyre. The method is performed on a rubber sample weighing approximately 3 grams and is based on an extraction and work-up as defined by ISO 4645/84 and ISO 1407/92. The analysis is then undertaken following IP 391/90. If the level of polycyclic aromatics (PCA) in the extract is greater than 15% then the tyre is judged to contain carcinogenic oils.

If a tyre is to be included in our list, the manufacturer or importer must have reported or advertised that the tyre treads are free from HA oils. The tyre must be able to pass a spot check analysis by the SP method.

The list only addresses car tyres. C-tyres are not included. Only tyres available on the Swedish market are accepted. The list should be considered as a guide to a more health- and environmentally adapted choice of tyres; it is not a government directive.

 
   

Read more (unfortunately not all in English)

Ahlbom, J. Duus, U. 1994. Nya hjulspår - en produktstudie av gummidäck. Rapport från Kemikalieinspektionen nr 6/94.

Andersson, J-E. 1998. Först ut att ersätta hälsovådlig och miljösuspekt olja i personbilsdäck. Continental Gislaved Däck AB. Föredrag på IVF, Mölndal

Carlsson, E. Johansson, T. 2002. Vertikal spridning av organiska föroreningar i vägdike. Vatten, Miljö, Transport. Chalmers Tekniska Högskola, Göteborg. Examensarbete 2002:2

Cedheim, L. et.al. 2000. Sammanfattande metod för att bestämma den totala halten PCA i extrakt från däck - ett underlag för miljömärkning. SP Sveriges Provnings- och Forskningsinstitut. Borås

Edlund, S. 2001. PAH as a POP - possibilities, implications and appropriateness of regulating global emissions of polycyclic aromatic hydrocarbons through the Stockholm Convention on persistant organic pollutants. Thesis for a M Sc. Environmental Management and Policy, Lund University, Sweden.

EU Directive 2005/69/EC of the European Parliament and of the Council of the 16th of November 2005.

EU Brite-Euram Thematc Network. 2000. Replacing polyaromatic hydrocarbons. www.rubber-compounding.com

Förlin et al. 2002. Biomarker responses and chemical analysis in fish indicate marked release of PAH from car tyre rubber. Department of Zoology, Göteborg University, Institute of Applied Environmental Research, Stockholm Universtity. Poster Paper Abstract presented at SETAC May 2002,Vienna.

Förlin et al. 2002. Biomarker responses in fish exposed to PAH and other additives released from car rubber tyres. Dept of Zoology, Göteborg University. Institute of Applied Environmental Research, Stockholm University. Poster Paper Abstract presented at XIth meeting of the Society for Free Radical Research, July 2002. Paris.

Holmgren, Anna. 1999. PAH-budget för Stockholm. Institutet för tillämpad miljöforskning, Stockholm Vatten. Rapport Nr 20, maj 1999.

Miljöförvaltningen i Stockholm Stad. 2002. PAH i sediment i Stockholmsområdet - halter och källor. Rapport från SLB-analys nr1:2002

Norin, M. 2001. Urlakning- och flödesprocesser vid mellanlag-ring av asfalt. Geologiska institutionen. Chalmers Tekniska Högskola. Göteborg.

Null,V. 1999. Safe process oils for tires with low environmental impact. Kautschuk Gummi Kunststoffe 52.Jahrgang, Nr 12/99.

Teknikens Värld. 1995. Vi hjälper dig välja bästa vinterdäck. Nr 19, 27 september 1995.

Teknikens Värld. 2001. Däcktest - 10 däck hårdkörda - de här törs du lita på. Nr 7. årgång 54, 29 mars 2001.

Teknikens Värld. 2002. Bästa vinterdäcken - sex dubbade och sex dubbfria i största testet. Nr 22, årgång 55, 22 oktober 2002.

Åkerman et al. 2002. Miljöövervakning i Stockholms kommun. Mälaren och Saltsjön - Biologi. Rapport: provtagningsåren 96/97, 97/98, 98/99. Institutet för tillämpad miljöforskning. Stockholms Universitet.

 
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