The threat to pine tar

Pine tar produced in traditional kilns was once known and marketed all over the world as   "Stockholm tar". It has been used for hundreds of years to preserve wooden vessels and it is still needed for maintenance of old wooden ships and boats.

Tar is a complex combination distillate containing thousands of substances, produced by the high temperature carbonization of pine wood in anoxic conditions (dry distillation).  It consists primarily of aromatic hydrocarbons, tar acids and tar bases. Components of tar vary according to the pyrolytic process (e.g. method, duration, temperature) and origin of the wood (e.g. age of pine trees, type of soil and moisture conditions during tree growth). The choice of wood, design of kiln, burning and collection of the tar can vary from burning to burning. Only stumps and roots of pine are used in the traditional production of pine tar.

Pine tar is needed to keep the surfaces, the materials and the colours of wooden vessels in good condition and to maintain their original appearance. The efficacy of pine tar for wood treatment is mainly based on physically blocking the porous structure of the wood material and making the material water proof. Pine tar has to be applied regularly to give the surface sufficient protection depending on the tar quality, building and construction details, the orientation and the local conditions. Tar is applied normally by a big brush. It is recommended to apply thick layers of tar to protect the wooden vessels/objects (for instance rigging) from water penetration and degradation by weathering.

The use of other products to preserve wooden historic vessels is highly unsafe and can lead to the destruction of the vessels through cracking of the wood etc. Without a pine tar treatment such a boat would leak and sink.

Recreational Craft Directive 94/25/EC Art. 1(3)(e) mentions "original and individual replicas of historical craft designed before 1950, built predominantly with the original materials and labelled as such by the manufacturer" and provides that these shall be excluded from the scope of this Directive. This definition applies to the kind of boats needs to be treated with traditional pine tar.

The guide to the Recreational Craft Directive explains that, according to the exclusion in clause (e), builders of historical craft are able to build the same authentic design, one boat after another. These boats are still unique and individual, when built using methods and materials consistent with the original design, and retain their aesthetic charm and characteristics. These boats are generally of a design pre-dating 1950 and built in specialist yards of original materials. The Member State must be satisfied that such an exclusion from the Recreational Craft Directive would not give carte blanche for series production.

According to the second Review Regulation the placing on the market of pine tar for wood preservation will no longer be possible after 1st September 2006.

The most severe impact will be that a certain key part of our Common European Maritime Heritage, traditional wooden boats and ships, can no longer be treated with wood tar. There are no suitable alternative chemicals for the treatment of wooden vessels. If they cannot be treated with pine tar, decay will gradually take place and in the long run the vessels will be destroyed completely. 

From the point of view of historical and cultural authenticity, no substitute for pine tar exists.  The loss of cultural heritage objects and cultural environment as a consequence of destruction or lacking maintenance cannot be accepted.

What to do now.

The Environment Directorate of the European Commission already restricts the marketing and use of various biocides considered hazardous to human health or to the environment. Currently these are Arsenic, Creosote, Mercury, Organic tin compounds and Pentachlorophenol. Pine tar is due to join this list in September 2006, but the Directorate  is considering applications for  ‘derogations’ from nations which can demonstrate that continued use of pine tar is essential. Applications have already been submitted from Denmark, Finland and Norway, all of which have relied for many centuries on pine tar to protect their historic wooden churches, bell-towers and other cultural monuments, as well as the hulls and rigging of their traditional ships and boats.

Each of these applications for a national derogation questions the assumption that pine tar works as a biocide, but asserts that its effect is to physically block the cells of the wood and prevent the ingress of moisture. Tests to confirm that pine tar is not an effective biocide have been commissioned by the Danish, Norwegian and Swedish authorities. But even using an accelerated weathering process to test the effect of the tar on wood exposed outside, the results of the trials (at a Swedish testing station) will not be available until September 2006, after the planned introduction of the EC embargo on the first day of that month.

If you use pine tar, and wish to continue to do so, you should ask your regular supplier whether he is aware of the intended ban on supplying it. The Environment Directorate in Brussels invites comments on the applications for derogations, which are posted on the website http://europa.eu.int/comm/environment/biocides/essential_uses.htm . But only 60 days are allowed for the submission of such comments, and the consultation periods will close in June. You should also consider contacting the relevant office within your own Government. In December 2005, the Environment Directorate in Brussels prepared a list of all the relevant contact points in EC countries, and a copy of this 24-page directory can be viewed and downloaded at http://europa.eu.int/comm/environment/biocides/pdf/ca_contact.pdf  

There are fears that, in those European nations where no derogation is granted to use pine tar on wood, the amount required for other maritime uses such as rigging and caulking will be so small as to be uneconomic for suppliers. Riggers and caulkers who habitually use pine tar for such purposes may now want to obtain sufficient quantities of pine tar to cover their anticipated requirements.

The Executive Committee of EMH is concerned that the case for and against the continuing use of pine tar must be fully investigated before any decision is made to prohibit its supply and use  under  Directive 98/8/EC (Biocidal Products)  of the European Parliament. Please act quickly if you wish to comment on any of the applications from the Nordic countries for national derogations, and contact the EMH Secretariat so that your voice can be added to the growing chorus of concern at this threat to a traditional and well-proved method of protecting timber, natural-fibre cordage and caulking against decay. Please make sure that  all existing users of pine tar in your country know of the intention to restrict its use. Specialist journals may be glad to give the matter editorial coverage, if you can give them the facts of the case. You may find it useful to contact Tom Rasmussen, Secretary of the Skibsbevaringsfonden in Denmark, who has been following the situation closely; you can email him on , Telephone/fax +45 7565 9919, mobile +45 2080 9518