2017 Antimony Day: Because we are stronger together
Caroline Braibant, Secretary-General of the International Antimony Association (i2a)
The International Antimony Association (i2a) organized its first Antimony Day in Brussels on 29 November 2017. The event gathered more than 100 representatives of the antimony value chain, including miners, producers, traders, and users, as well as press, the scientific community, and European authorities. The aim of the day was to raise awareness about the revamped regulatory scrutiny on antimony substances, and to call the value chain to collaborate with and support i2a in addressing the authorities’ request for exposure evidence.
Since the release of the results of the NTP inhalation carcinogenicity studies in 2016, new animal toxicological evidence needs to be considered for the classification and risk assessment of antimony trioxide and other related antimony substances. In the EU and the US, this evidence is subject to specific evaluation processes. Under EU-REACH, this process is called Substance Evaluation and will commence formally under the leadership of German REACH authorities (BAuA) in Spring 2018. Substance Evaluation is the regulatory step taken by authorities to gather all relevant information before concluding on the applicable classification and on the possible risks related to the use of substances, and subsequent risk management measures to be implemented to control that risk (e.g. with an Occupational Exposure Limit or OEL, or a number of use-specific restrictions).
There are two main endpoints which need to be reassessed in light of recent evidence: lung toxicity and reproductive toxicity. Investigations assessing the possible reproductive toxicity of antimony substances, points towards no impacts upon fertility and no, or comparatively mild, developmental toxicity, always related to maternal toxicity. Unless a classification is warranted for this endpoint, REACH foresees additional tests to be performed, which constitute a very significant cost and possibly a misuse of laboratory animals. Lung toxicity has manifested itself as pneumoconiosis in workers exposed to very high (historical) levels of antimony substances, before the implementation of the current OEL of 0.5mg/m³, and as cancer in laboratory animals. This requires deciding on whether the Carcinogenicity Category 2 classification of Antimony Trioxide should be ‘upgraded’ to a Category 1B, whether or not similar health effects are observed in humans.
During the Day, authorities made the point that classification is subject to rigid rules laid down in the CLP regulation, which do not take account of particle size or exposure potential. Classifications are derived on the basis of animal study results, which are known to be specifically designed to reveal some toxic effect at the highest dose used. All substances are potentially toxic; their toxicity will occur at or above a specific dose or concentration, which varies across substances, but is not necessarily reflected in the resulting classification. The classification of antimony substances will be subject to these abstract theoretical rules, and will not reflect the actual risk of using the substances.
Risk is determined by both hazard (classification) and exposure. Hazardous substances with no or controlled exposure can be safe to use.
For BAuA to assess this safety, they require exposure evidence, i.e. exposure data that can be compared and shown to be below the dose at which toxic effects may occur. This exposure data needs to be collected from workplaces of producers and users of antimony substances. During the Antimony Day, several participants confirmed that air levels of antimony in the workplaces are being monitored, and that the sector has been innovating into the production of non-dusty forms of antimony substances, so as to minimize and prevent any exposure. BAuA welcomed this initiative and called for actual evidence to be provided via i2a, who can submit this data through the respective REACH dossiers.
Following a scene-setting morning session, the afternoon session of the Antimony Day was dedicated to collect specific views and input from every segment of the antimony value chain. The representatives were organized in breakout groups with dedicated facilitators invited to gather supply chain-segment specific answers on the following three questions:
- What would be the impact for you of a more severe classification?
- What data do you have to mitigate this worst-case scenario?
- Are you willing to generate any missing data?
The main common impact of a reclassification across the various segments of the value chain is the cost related to the relabeling, repackaging, and transport requirements, as well as the ‘black-listing effect’ and resulting communication needs with customers. Some uses may decrease as a result of these increased compliance costs, and smaller companies may be unable to carry the weight of this cost and may have to close down. The actual impact will however be specific for each antimony substance, as they have different toxicity and use profiles. There are two sets of evidence that should be populated: one to specify an exposure route for the carcinogenicity classification, and one to demonstrate the low and controlled exposure there is in workplaces where antimony substances are produced or used. If the scope of the carcinogenicity classification specifies the inhalation exposure route, only physical forms which can be inhaled (i.e. powders) of the classified antimony substances would need to be relabeled, repackaged or subject to new transport requirements. Forms which are not dusty or inhalable would not be affected. Demonstration of no or controlled exposure would comfort authorities that no further risk management measures are needed and that uncertainty assessment factors used in a number of their assessments can be reduced, yielding more realistic thresholds and safety levels to comply with.
Existing data may not be sufficient to demonstrate that the carcinogenicity effect is only taking place via inhalation, or that exposure is controlled and low in all producing and using sites. Provided there is a structured plan and demonstrated business case to generate missing information, all segments of the antimony value chain confirmed their willingness to generate missing data. Importantly, several representatives requested that more socio-economic cost/benefit evidence is generated too, in order to strive for realistic and proportionate information requirements and regulatory decisions.
In the so-called Solutions Panel, the battery, flame retardant textiles, PET and plastic masterbatches sectors further discussed the role of i2a and the antimony value chain in addressing the identified information requirements and authorities’ requests. It was generally agreed that i2a should centralize the various information generation initiatives, and be the main communication channel with REACH and other authorities evaluating antimony substances, such as the NTP.
The various evaluations and decision-making on antimony substances will take until 2020, just about the time needed for Industry to implement a consolidated and routine exposure monitoring program, and regular updates of the classification and risk assessment datasets in the form of REACH dossiers. The Antimony Day has prompted many follow-up exchanges between i2a and possible Members and collaborators. The event enabled both awareness-raising and constructive networking for many in the value chain, and should be reproduced to maintain the momentum and build a sustainable and responsible Sb industry, where Sb substances continue to be the material of choice for many technology-enabling applications.
The call for information, collaboration and support will be made with the Asian part of the antimony value chain, at the conference organized by Argus in Singapore on 28 February and 1 March 2018.
The next Antimony Day will take place in Brussels on 14 November 2018, and will focus on flame retardant applications of antimony substances. More information can be found here.
US National Toxicology Program
EU regulation on the Registration, Evaluation and Authorization ofChemicals
EU regulation on the Classification, Labelling and Packaging of Chemicals