The coating industry and its suppliers in Europe have been issuing dire warnings about a move in the European Union to classify titanium dioxide as a hazardous substance.

The Helsinki-based European Chemicals Agency (ECHA), which is responsible for the implementation of the EU’s main industrial chemicals legislation, is currently assessing a French proposal that TiO2 be categorized as dangerous on its labels due to it being possibly  carcinogenic through inhalation.

“This is an initiative whose results could be drastic,” said Janice Robinson, product regulations director, at the European Council of Paint, Printing Ink and Artists’ Colours Industry (CEPE), Europe’s main coatings trade association.

CEPE has issued a statement listing several major consequences if the European Commission, the EU’s Brussels-based executive, decides to support a recommendation that TiO2  be classified as hazardous under the  Union’s system for  the harmonization of classification and labeling of  dangerous chemicals.

At the moment, under the EU’s Classification, Labeling and Packaging (CLP) regulation, the pigment is effectively considered to be a benign chemical without the need for a danger warning.

An immediate consequence of it being classified under the CLP rules as being inherently hazardous would be that under the REACH legislation, which, with the CLP regulation, are two major pieces of chemicals legislation run by ECHA, products like decorative paints containing possible carcinogens cannot be sold  to consumers. This would mean that decorative coatings could not be marketed directly for DIY purposes but would have to be sold only to professional painters or industrial users.

Within coatings production plants, companies would almost certainly have to take mandatory precautions to protect workers from the newly perceived dangers of TiO2 which would raise  manufacturing costs.

However, the biggest long term impact would come  from TiO2   being automatically  classed as a substance of very high concern (SVHC) under REACH  because of its  being carcinogenic. 

This would raise doubts about the commercial viability of products containing TiO2 – not only coatings, but also inks, plastics and sunscreen protectors. End users, particularly consumer brand owners and retail chain, are treating SVHCs  with extreme  caution, in some cases blacklisting them.

The main objective behind the creation of the SVHC category is that chemicals within it will have to be authorized by the European Commission on the recommendation of ECHA to be marketed within the EU. Ultimately SVHC substances would be replaced by safer alternatives.

Another major threat is that substances with TiO2’s similar potentially dangerous properties of having particles which once inhaled can be hazardous because of their low solubility or  insolubility will be given an  identical  classification.  These will also be given the SVHC tag and be destined for authorization.

“TiO2 is not the only substance with these levels of low solubility or insolubility,”  explained Anthony Jones, chairman of the Titanium Dioxide Industry Consortium  (TDIC), a sister organization of the Brussels-based Titanium Dioxide Manufacturers  Association (TDMA). “Other chemicals with similar properties include calcium carbonate, silicas and carbon black.”

The French proposal to ECHA argues that  TiO2  should be classified as a carcinogen 1b ( figure ‘1’ and letter ‘b’) or a substance presumed to have carcinogenic potential for humans. 

In a report on the proposal, France’s Agency for Food, Environmental and Occupational Health & Safety (ANSES) cites evidence from the Paris-based International Agency for Research on Cancer (IARC), which in 2006 classified TiO2 as a substance “possibly carcinogenic to humans.”

The data from two animal studies conducted in the 1980s demonstrated that TiO2 can cause malignant tumors in rats following exposure by inhalation, according to ANSES.

“Because of its physico-chemical properties, exposure to titanium dioxide by the respiratory route, at a certain level of concentration, may cause lung overload and lead to an inflammatory reaction, responsible for proliferative lesions,” said the agency, whose proposals covers TiO2 in all its crystalline phases and combinations of phases, sizes and shapes of particles.

Under ECHA’s procedure for dealing with cases for classification and labeling harmonization, the French proposal  has been put out for public consultation.  Then ECHA’s  risk assessment committee (RAC) has 18 months or before the end of 2017 to make a recommendation to the European Commission.

The RAC, comprising experts from the EU’s member states on toxicology, has to determine only whether the chemical is  inherently hazardous not the degree of its risk or level of exposure.

There are a number of points which indicate that the committee is likely to come out against classification of TiO2 which is  currently considered to be a relatively safe chemical throughout the  world.

First, the studies carried out in the 1980s on rats involved a  high  ‘overload’ dosage of  TiO2 – 250 milligrams per cubic meter which was 25 times the occupational exposure limit in Europe.

Since then the Organisation for Economic Co-operation and Development (OECD), the Paris-based agency for the world’s rich countries, has drawn up guidelines on animal testing limiting doses to 25-50 mg per cubic meter.   ECHA uses OECD guidelines as criteria in its assessments of data so it is unlikely to go against a guideline from the organization on this occasion.

“In fact the studies included data from dosages below and within these guideline limits and the one at 250 mg was the only one which resulted in the formation of tumors,” said Jones. 

“Furthermore, the effects were very much rat specific,” he continued.  “Similar tests have been done on mice and hamsters without carcinogenic effects.  Rats have a different response mechanism. These tests with rats cannot be applied to humans.”

The TDMA  has also been collecting epidemiological evidence verifying the safety of TiO2 through exposure data.  This cannot be considered by RAC  because it is not  relevant to the issue of  TiO2  being inherently hazardous.

But in what will be a highly controversial matter if RAC supports classification of TiO2,  socio-economic issues may have to be considered by the European Commission before it takes the final decision.

“Epidemiological studies of over 20,000 workers exposed to TiO2   for several decades shows  no evidence of occupational cancer, which is something that hopefully will be taken into account,” said Robinson.

The key factor dictating the final decision will be the futures of  not only  the coatings industry but all the other sectors using TiO2, as well as those applying  substances with the similar bio-persistent properties of low or non-existent solubility.