Derivation of control strategies. Occupational safety and health in practice Example new technologies: nanomaterials.

Transcription

1 Developing Reference Methods for Nanomaterials Occupational safety and health in practice Example new technologies: nanomaterials Presentation No 5

2 Imprint This presentation is a final product of the project NanoValid - project F and was generated under the lead responsibility of Miriam Baron (Federal Institute for Occupational Safety and Health). The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/ ) under grant agreement n (NanoValid Development of reference methods for hazard identification, risk assessment and LCA of engineered nanomaterials). The responsibility for the contents of this publication lies with the authors. Copyright 2015 by the authors Project monitoring and main author: Miriam Baron Federal Institute for Occupational Safety and Health (BAuA) With contributions from: Rolf Packroff, Michael Roitzsch, Dag Rother, Aart Rouw, Torsten Wolf Federal Institute for Occupational Safety and Health (BAuA) Shashi Singh Centre for Cellular & Molecular Biology Damjana Drobne University of Ljubljana Figures: Miriam Baron Federal Institute for Occupational Safety and Health (BAuA) Fox / Uwe Völkner Project support: Elke Kahler-Jenett, Katharina Niesmann Federal Institute for Occupational Safety and Health (BAuA) Design: Carolin Schneider, eckedesign Berlin Editing: Johanna Ebbeskotte, Markus Flender Federal Institute for Occupational Safety and Health (BAuA) Publisher: Federal Institute for Occupational Safety and Health (BAuA) Friedrich-Henkel-Weg 1-25, Dortmund, Germany Nöldnerstr , Berlin, Germany Telephone NanoValid: Project Coordinator: Rudolf Reuther, Nordmiljö AB rudolf.reuther@enas-online.com Telephone (Sweden) or (Germany) All rights reserved, including photomechanical reproduction and the reprinting of extracts. First published: July

3 Slide 1: How large is the Occupational Safety and Health problem concerning nanomaterials from the view of safety experts? How large? What about the size? Does the risk end at 100 nm or do we have other ranges? Is the problem bigger than just nanomaterials and do we need to expand it to respirable dusts and fibers? How big? Are nanomaterials more toxic or more carcinogenic and if yes, does this affect the control strategy? 3

4 Slide 2: Overview The complex world of nanomaterials Challenge for occupational safety Hazard Potential Information gathering and safe design of workplaces Exposure assessment Risk assessment Toxicology 2 Firstly, I will present an insight in the complex world of nanomaterials. Nanomaterials are various / different. The control strategies for workplaces need to be adapted accordingly. Then I will elaborate on the aspects toxicology, risk assessment All these factors are required to derive adequate control strategies and safe design of workplaces. 4

5 Slide 3: Possibilities for substitution Substitute hazardous substances by substances with less hazardous properties Low dustiness substance or process: Bind nanomaterials into liquid into solid matrices Humidify the raw material, use granulates, pastes or ready-mixed materials Silo instead of bagged cargo Regard proportionality Not only for nanomaterials, dust issue! 3 The safety strategy is based on the STOP principle, which determines the hierarchy of protection measures: 1.) substitution, 2.) technical measures, 3.) organizational measures, 4.) personal protective equipment. The first thing to do is to try to substitute hazardous substances by other substances with less hazardous properties. This can refer to a lower dustiness of the substance or process: For instance by binding nanomaterials into liquid or solid matrices Humidify the raw material, use granulates, pastes or ready-mixed materials Use silo instead of bagged cargo (cement containing nanosilica) In case of substitution, one should regard the proportionality. Of course, a substitution is no special issue for nanomaterials. Here, one takes a closer look on the dust issue! 5

6 Slide 4: Strategy for nanomaterials in liquid with aerosols? Substitute with low-aerosol process (brush instead of spray) Consider if explosion protection is required: explosion-proof stirrer (ATEX directive), grounding, pressure relief, conductive safety shoes Photo: FOX / Uwe Völkner If required, personal protective equipment (PPE): Body: Protective suit with splash guard (type 4) respiration: particle filter P2 hands: ask glove manufacturer for suitable glove material, consider solvent 4 Substitute with low-aerosol process (brush instead of spray) Consider if explosion protection is required: explosion-proof stirrer (according to ATEX directive), grounding, pressure relief, conductive safety shoes If technical and organizational measures are not sufficient or applicable, personal protective equipment (PPE) is required: Body: Protective suit with additional splash guard (type 4) respiration: wear mask with particle filter P2 hands: ask glove manufacturer for suitable glove material, consider compatibility with solvent 6

7 Slide 5: Technical protection measures Inhalative hazard Closed system, relief for small amounts In other case (generally): reduce dusts and aerosol formation, local exhaust ventilation (LEV), regular maintenance, no air recirculation without air treatment Photo: S. Plitzko, BAuA Recommendation for nanomaterials: low penetration filter (0.005%, dust class H), depending on risk assessment: fume hood for vapours for instance of solvents (sol gel process), safety bench or glove box for dusty nanomaterials 5 As far as possible, a closed system should be used. For small amounts, fume hoods, safety cabinets and fume hoods are presumed as emission-free. If a closed system is not applicable, it is recommended to: Reduce dust and aerosol formation, Install a local exhaust ventilation (LEV) directly at the source, And regularly maintain the LEV. An air recirculation without air treatment is not allowed. For nanomaterials, it is recommended to use a low penetration filter (0.005 %, dust class H) for the exhaust air. Depending on risk assessment, fume hoods for vapours for instance of solvents (sol gel process) or safety benches or glove boxes for dusty nanomaterials are recommended. 7

8 Slide 6: Organisational protection measures Course of instrucion: explanation, what nanomaterials are, properties of the respective nanomaterial, safety risks caused by nanomaterials (fire and explosion), activitieswith high exposure Adaption of working instruction Cleaning: wet process no strong water jet (friction, dust is raised), vacuum cleaner of dust class H, NO blowing off with compressed air Photo: Working instruction 6 The employer is obliged to instruct the employees. A course of instruction can contain: An explanation, what nanomaterials are, Information about the properties of the respective nanomaterial, Potential safety risks caused by nanomaterials (fire and explosion), Information about activities with high exposure The working instruction shall be adjusted accordingly. Recommendations for cleaning dusty nanomaterials are: For cleaning with a wet process, do not use a strong water jet, since friction can occur or dust can be raised. Use a vacuum cleaner of dust class H. It is NOT permissible to clean the working area or blowing off dust deposits with compressed air 8

9 Slide 7: Working instruction For instance Photo: Working instruction 7 The adaption of the working instruction could include for example: Risks to human health or the environment: The substance has not been tested completely yet. Protective measures and rules of conduct: Avoid dust generation 9

10 Slide 8: Personal protective equipment During accompanying and short open activities like filling, sample taking and cleaning and maintenance Protective suit: no cotton wool, but for example highdensity polyethylene (HDPE) or similar (confirmedby NanoSafe 2) In case of dust: dustproof protective suit type 5 Gloves: for example nitrile or neoprene (confirmed by NanoSafe 2) Respiratory protection: Efficacyalso dependent on tight fit Particle filter P2 or P3 Photo: Dust mask 8 If technical or organizational protective measures are not sufficient or cannot be installed, PPE needs to be applied additionally. This can be the case during accompanying and short open activities like filling, sample taking and cleaning and maintenance. PPE can be: Protective suit, which does not consist of cotton wool (too porous). It can consist for example of high-density polyethylene (HDPE) or a similar material. The material resistance was confirmed by the project NanoSafe 2. In cases where a high load of dust is generated, a dustproof protective suit type 5 is recommended. Gloves: For dusty nanomaterials, gloves provide a sufficient protection. They can be made for example from nitrile or neoprene (confirmed by NanoSafe 2). The efficacy of a respiratory mask also depends on its tight fit. For activities with dusty nanomaterials, half- or full face masks with particle filter P2 or P3 shall be used. 10

11 Slide 9: Efficacy of filtering materials General view on filter: sieve Particles < 300 nm: Precipitation also by diffusion and electrostatic forces Conventional technical measures, which are effective for dusts, also work on nanoparticles and ultrafine dusts Transmittance of P2- and P3-filter corresponds to the standards: tested by IFA with nanoscaled cooking salt particles or by Rengasamy et al. with nanoscaled silver- and cooking salt particles Photo: A. Rouw, BAuA 9 Due to the partly new and unique properties of nanomaterials, one often assumes that the conventional safety strategies might not work for nanomaterials. For filters (respiratory protection, ventilation) the picture of a sieve, where the particles can slip through, is often used. However, particles > 300 nm are physically caught by the filter material or are separated by gravity, whereas particles < 300 nm additionally precipitate by diffusion (Brownian motion) and electrostatic forces. For this reason, one can assume that conventional technical measures, which are effective for dusts, also work on nanoparticles and ultrafine dusts. This was verified by measurements. The IFA (Institute for Occupational Safety in Germany) tested nanoscaled cooking salt particles and found a filter transmittance of only 0.2 % respectively 0.01 %. Rengasamy et al. tested nanoscaled silver- and cooking salt particles and concluded a transmittance of < 2.2 % respectively % for FFP2 and FFP3 masks. So, the transmittance of P2- and P3-filter corresponds to the non-nano standards. 11

12 Slide 10: Further aspects relevant for risk assessment Depending on the specific substance properties: Explosion protection for oxidisable nanomaterials Specific protection measures for handling reactive or catalytically active nanomaterials Generally compliance of further measures resulting from the risk assessment (for instance compliance with threshold values of solvents) 10 Depending on the specific substance properties, further protection measures can be required: For instance explosion protection for oxidisable nanomaterials, Or specific protection measures for handling reactive or catalytically active nanomaterials. Despite the specific safety strategy on the respective nanomaterial, all further measures resulting from the risk assessment (for instance compliance with threshold values of solvents) are to be complied with. 12

13 Slide 11: Explosion protection Increased risk to explosion of nanoscaled dust due to decreased particle size A grain size 500 µm can result in the generation of explosive dust-air-mixtures Check explosion protection measures, for instance: During filling dust raising nanomaterials During removal of flammable dusts 11 Nanoscaled dust can exhibit an increased risk to explosion due to decreased particle size and thus higher surface area ratios. A grain size 500 µm can result in the generation of explosive dust-air-mixtures. Check explosion protection measures, for instance: During filling of dust raising nanomaterials During removal of flammable dusts 13

14 Slide 12: Recommendations for explosion protecion measures Usage of explosion protected devices according to directive 94/9/EG (so-called ATEX equipment) Usage of suitable pumps and ventilators For example explosion-protected stirrer Appropriate grounding of the equipment Pressure relief Usage of conductive safety shoes Especially the vacuum cleaner shall meet the equipment requirements (directive 94/9/EG) according to the existing explosive atmosphere Photo: FOX / Uwe Völkner 12 Examples for explosion protection measures are: Usage of explosion protected devices according to directive 94/9/EG (so-called ATEX equipment) Usage of suitable pumps and ventilators For example explosion-protected stirrer Appropriate grounding of the equipment Pressure relief Usage of conductive safety shoes Especially the vacuum cleaner shall meet the equipment requirements (directive 94/9/EG) according to the existing explosive atmosphere 14

15 Slide 13: Recommendations for removal Collect waste in a labelled closed container (for instance clamping ring barrel): Attention contains waste of a not completely tested substance Consider the disposal structure of the respective member state (and consider regional rules): substance-specific criteria, European waste catalogue Consult the waste disposal company in case of open questions No general solution, but individual case, inactivation in a matrix for example, for CNTs combustion above 500 C (complete oxidation) reasonable 13 Collect waste in a labeled closed container (for instance clamping ring barrel): Attention contains waste of a not completely tested substance. Consider the disposal structure of your respective member state. It generally meets the environment and safety standards also for waste containing nanomaterials. The substance-specific criteria and the European waste catalogue should be taken into account. Consult the waste disposal company in case of open questions concerning the proper removal. The hazard and the properties of waste can generally be changed by stabilization and solidification. However, there is no general solution, but specifically adapted processes. As an individual case, nanomaterials can be inactivated in a matrix for example. For CNTs, a combustion above 500 C is reasonable, since complete oxidation takes place at this temperature. For the individual case, consult an expert. 15

16 Slide 14: Conclusions As always and for every chemical there will be open questions left Like for many other chemicals, we still find knowledge gaps regarding the health risks. We want to recognize the risks at an early stage. Many questions already answered Scientific knowledge on fine- and ultrafine dusts, fibres and chemical substances is a good starting point. Risk assessmentstrategies can be developed Nanomaterials can have different hazardous potentials (effect and release potential) Nanoscaled cannot be equated with hazardous. It is the respirable (nano-)dust that matters most! For occupational safety, the precautionary approach and the classical dust safety strategies are a good basis. 14 Don t forget, granular or fibers it is the respirable dust (particle and fiber dust) that matters as well as biopersistence. For occupational safety, the precautionary approach and the classical dust safety strategies are a good basis. 16

17 Slide 15: Thank you! Thank you for your attention! 15 17