In 2004, the first International Symposium on Occupational Health Implications of Nanomaterials was held in Buxton in the UK.  Seven years later, I’m preparing for a discussion panel at the fifth meeting in this very successful community-led series (being held this week in Boston MA), and looking through the research recommendations we made at the Buxton meeting.  Disturbingly, they look remarkably similar to recommendations still being made.

The report from that original meeting can be found here, although I have also reproduced the research recommendations from that report below.  As there are a rather lot of recommendations (and I need to cover these in some rational way in this Friday’s discussion panel), I thought it would be interesting to filter them through the Wordle Creator.

This is what I got:

Of course things have moved along a lot in some areas over the past few years, and in some cases priorities have changed and new priorities have arisen.  But looking at the – admittedly qualitative – Wordle, it’s remarkable how many of these old issues remain contemporary issues.

So are we making progress, or are we simply going round in circles?  This is what I hope to tease out of my panel of experts this Friday!

In the meantime, here are the research/action recommendations we made back in 2004:

6.2 RECOMMENDATIONS FOR FILLING GAPS IN KNOWLEDGE

The following recommendations were made within the workshops addressing current knowledge gaps in understanding the potential health implications of nanotechnology in the workplace. Inclusion in this report does not constitute endorsement by NIOSH and HSE

6.2.1 Measurement of exposure to nanoparticles

1. there needs to be internationally agreed definitions of the particles that we should be measuring to assess exposure.

2. the health-related importance of agglomerated nanoparticles as opposed to single discrete nanoparticles should be addressed to ensure that measurements include all particles that may have health effects.

3. further research is needed to define the biologically relevant parameters that should be measured.

4. until more is known about which parameters should be measured, it is recommended that multiple parameters should be measured in parallel, if possible. Information is then gained about relationships between parameters to allow links with past exposure data.

5. simple, relatively cheap personal monitors for measuring exposure to nanoparticles should be developed. These should be for particle surface area or number as they are likely to be the most biologically relevant parameters.

6. as a crude identification of nanoaerosol emissions, the measurement of particle number concentrations using a hand-held CPC is considered to be useful as a process control tool.

7. strategies for differentiating between new engineered nanoparticles and ambient combustion-derived nanoparticles should be developed.

6.2.2 Control of exposure to nanoparticles

1. the effectiveness of engineering control methods, such as containment, local exhaust ventilation (LEV) systems, etc., in controlling exposure to nanoparticles should be assessed.

2. the efficiency of HEPA filtration systems used in extraction equipment fitted to LEV system (especially where the air is recirculated) and vacuum cleaners should be assessed for nanoparticles. The integrity of seals is particularly important.

3. research and development should be carried out to improve the control of exposure to nanoparticles during breakdown, maintenance and clean up procedures.

4. the propensity for powdered nanomaterials to release nanostructured particles into the air should be assessed. The usefulness of current methods of dustiness testing for nanomaterials should be investigated.

5. mechanisms should be put in place to enable good control practice for nanoparticles to be shared between companies and industry sectors.

6. the efficiency of respiratory protection equipment for minimising exposure to nanoparticles should be investigated, especially in terms of face-seal leakage and for very small particles (< 5nm).

7. the penetration of nanoparticles through skin protection equipment (gloves, boiler suits, etc) should be investigated.

6.2.3 Mechanisms underlying toxicity of nanoparticles

1. the possible mechanisms by which engineered nanoparticles have the potential to translocate through the body and to affect cells in host organs should be further investigated at the molecular level.

2. the effect of the state of aggregation on the toxicity of nanoparticles should be investigated.

3. work should be carried out to determine the relative contributions to adverse health effects of the generic size of the nanoparticle and the role of surface chemistry including any agent that it may carry.

4. relevant test methods should be developed to investigate the genotoxic hazards and risks of nanoparticles in their various applications.

5. it was suggested that OELs exposure limits are still set on a mass basis as well as on data including surface area and particle number.

6. screening methods should be developed for new nanoparticles that are based on biochemical mechanisms and susceptible targets.

7. existing data on toxicity of other particulate materials should be used for comparison of hazards.

8. more relevant (in-vivo) screening methods should be used to assess potential mutagenicity of nanoparticles.

6.2.4 Human experience in exposure to nanoparticles

1. a multidisciplinary approach was necessary to investigate the health effects of nanoparticles, including toxicological mechanisms of action.

2. an agreed definition of nanomaterials and nanoparticles is required.

3. an agreed exposure metric is required.

4. development of practical devices which, with development of agreed exposure measurement techniques, would enable reliable measurement of workplace exposures to nanoparticles is required.

5. no agreed health surveillance approaches were identified.

6.3 RECOMMENDATIONS FOR REGULATORY ACTION ON THE CONTROL OF EXPOSURE TO NANOMATERIALS

The views and recommendations expressed in this section are solely those of the workshop participants in the First International Symposium on Nanotechnology and Occupational Health. Inclusion in this document does not constitute endorsement by NIOSH or HSE.

6.3.1 Regulations for nanomaterials

When occupational health and safety regulatory authorities review the adequacy of their regulations with respect to nanomaterials the following issues should be considered:

1. determine the number of people exposed and at what levels;

2. evaluate whether mass-based exposure limits are adequate;

3. investigate what measurement methods are available;

4. review adequacy of personal protection equipment for nanoparticles;

5. determine if there are any susceptible groups in the workforce;

6. evaluate whether a “skin” notation is needed;

7. consider the adequacy of labelling and of the material safety data sheets;

8. evaluate whether nano-forms of a material should be considered to be a new substance (as in Notification of New Substances [NONS] regulations);

9. develop a framework to categorise or group nanomaterials for hazard classification and exposure limits;

10. recommend interim measures and generic approaches until more specific information is available on risk from nanomaterials.

The current regime was considered to provide an adequate framework for regulations with the following suggestions for improvement:

1. determine if current toxicological protocols are adequate;

2. evaluate (as an EU.-specific issue) whether current production triggers (in NONS) are suitable for nanomaterials;

3. consider establishment of new ultrafine sampling convention;

4. ensure that regulations are internationally harmonised.

6.3.2 Occupational exposure limits

1. it was concluded that there was currently insufficient data upon which to set any occupational exposure limits (OELs) for nanoparticles.

2. the one exception was nano titanium dioxide particles for which there is a reasonable data on pulmonary and dermal toxicity.

3. as a way forward to enable safe production of nanomaterials, it was recommended that best practice in controlling exposure be deployed.

In order for regulatory authorities to set OELs for nanomaterials, the following was recommended:

1. substantial research funding should be available to conduct exposure and toxicity studies on new and existing nanomaterials;

2. exposure and toxicity studies should be carried out by multidisciplinary teams;

3. consideration should be given to co-exposures, synergisms, exposure modifiers, smokers, sensitive populations;

4. animal toxicity studies should include multi-generational studies.

6.3.3 Risk assessment and exposure control

1. it was concluded that there is insufficient information to determine whether current methods to assess risk and control exposure are adequate.

2. the process of risk assessment for nanomaterials should begin with approaches used for traditional workplace exposures, treating nanomaterials as a distinct topic.

3. research on the adequacy of current methods of control should carried out as soon as possible.

4. specific recommendations for good control practice should be developed.

5. it was recommended that a hierarchy of controls specifically targeted at nanomaterials should be produced.

In order to manage the production and use of nanomaterials in a safe way the following interim measures were proposed:

1. examine and build on our knowledge about “known” categories of ultrafine particles such as diesel exhaust and welding fumes.

2. assemble specific examples of when nanoparticle risks or nanotechnology process risks are less than or greater than risks for materials or processes involving “traditional” materials.

3. take advantage of opportunities to limit occupational exposures to nanomaterials to levels that are as low a reasonably achievable.

4. develop methods to identify manufactured nanoparticles in the presence of background particles.

5. identify suitable nanomaterial surrogates for use in studies to improve instrumentation, control technology, and toxicology for nanomaterials.

6. develop and disseminate nanoparticle assessment and control strategies for small and medium enterprises (e.g., “risk management” or “control banding” toolboxes).

7. seek global harmonisation of approaches.

8. establish easily accessible databases and information sources.

9. improve the content of Material Safety Data Sheets (MSDS) and other communications.

10. maintain a sense of urgency to answer practical questions now and to establish partnerships and approaches needed to address underlying questions of risk assessment, control, and toxicity mechanisms for nanomaterials.

6.3.4 Classification of nanomaterials

1. there is a need for new nomenclature to allow nanomaterials to be clearly identified and described.

2. current nomenclature and means of describing complex materials in NONS are not sufficient for nanomaterials.

3. materials in particles less than ~100 nm were considered to behave differently than micrometer-sized particles.

4. the current regulatory system was considered to be inadequate to control exposure to nanomaterials.

5. it was recommended that in the EU, all materials under an agreed particle size (possibly < 100 nm) should be considered new materials for NONS and REACH. (delegates were split on this recommendation).

6.3.5 Risk management

1. there is no need for a new risk management paradigm when considering the production and use of nanomaterials.

but there is a need for new tools to increase understanding of each part of the current risk management paradigm. They are:

consider adopting the precautionary principle;

reduce uncertainty by increasing knowledge through science;

consider perception or risk issues such as external risk, subjective human 
experience of risk and quality of information;

understand the paucity of information on the possible long-term effects such as 
carcinogencity, foetal exposure, neurotoxicity and cardiovascular effects and on the population at risk including the workforce and susceptible groups such as children and the elderly.

The complete report from the 2004 Buxton meeting is available at www.hsl.gov.uk/media/1646/nanosymrep_final.pdf

Update 8/11/11: Link to 2004 Buxton meeting report corrected