With the dramatic increase of nano-enabled products entering the market every year, human and environmental exposures are inevitable, which raises concerns in terms of the health and safety of such emerging nanomaterials. Scientific knowledge to assess the exposure to nanomaterials continues to improve. As an example, new exposure tools and models for nanomaterials are being developed. To further promote the development in this area, the OECD compiled an inventory of available models and tools for assessing occupational, consumer and environmental exposure to Nanomaterials. 54 tools and models were initially compiled and following in-depth analyses, 10 occupational, 7 consumer and 6 environmental tools/models were recommended or evaluated as suitable for assessing exposure to nanomaterials. The detailed information on the analyses and evaluations are provided in the reports accessible from the Series on Nanomaterials website (No. 98, 99, 100 and 101). The OECD hosted a webinar on 2 December at 14:00 CET to present the key findings of the reports. Watch the video replay at: https://oe.cd/testing-assessment-webinars

1. Assessing the Global Readiness of Regulatory
and Non-regulatory Models for Assessing
Occupational Exposure to Manufactured
Nanomaterials
Lead: Denmark (NRCWE); co-lead: USA (CDC-NIOSH)
Webinar 2 December 2021 - How to access exposure to
nanomaterials?
The evaluation result of existing tools/models

2. Introduction
Background
Part I
Part II
Policy implications and next steps
Summary
Content

3. • This work was conducted together with
from Denmark
• Co-lead with CDC-NIOSH
• Close collaboration with Health Canada
(Consumer Project)
Introduction
Ana Sofia
Fonseca
Keld Alstrup
Jensen

4. Introduction
 3 comment rounds
 Total of 140 comments
 From 5 institutions and 3
countries (Netherlands,
Germany and USA)
Milestone Date
Start of the project 2018
Finish of tools inventory February 2019
Finish of case studies collection December 2019
Joining forces with Health Canada (Consumer exposure project) May 2020
Submission of draft reports for revision to SG8 members June 2020
Comments to draft reports received August 2020
Submission of draft reports for revision to SG8 members October 2020
Comments to draft reports received December 2020
Submission of draft reports for revision to WPEA and WPMN February 2021
Comments to draft reports received April 2021
Final revision and submission of updated draft reports to WPMN June 2021
Acceptance October 2021

5. • Need to assess occupational exposure for different processes and
materials
• Occupational exposure measurement are costly and time
consuming
• Exposure assessment tools and models can be helpful
Background

6. Background
Conventional chemical tools/models
Few currently internationally recommended in
regulatory guidance documents
None was developed, tested, calibrated and validated
for assessment of occupational exposure to
manufactured nanomaterials
Objective: evaluate to what extent these different tools are
applicable and suitable to assess occupational exposure to
nanomaterials
New nano-specific tools/models
Early development stages
None accepted/recommended at regulatory level
Additional validation is required

7. Part I

8. Part I
nº Tool Tier Tool Type
1 ISO/TS 12901-2:2014 CB nanotool v1.0 1 Control Banding
2 BIORIMA (Occupational exposure section) 3 Quantitative Exposure Assessment
3 ENAETool (CPSC ENP Model) v1.0 3 Quantitative Exposure Assessment
4 Control Banding Nanotool v2.0 1 Control Banding
5 LiCARA nanoSCAN v1.0 1 Risk Benefit
6 NanoSafer v1.1β 2 Control Banding / Risk Management
7 GUIDEnano tool 3 Risk Assessment / Risk Management
8 SUNDS 3 Risk Assessment / Risk Management
9 ANSES tool 1 Control Banding
10 Swiss Precautionary Matrix v3.0 1 Risk Categorization
11 Stoffenmanager Nano v1.0 2 Control Banding / Risk Management
12 ConsExpo Nano 3 Physical modelling / Quantitative Exposure Assessment
13 NanoRiskCat 1 Risk Categorization
14 RISKOFDERM 2 Quantitative Exposure Assessment
15 MEASE2 2.0 2 Control Banding
16 EMKG Expo tool 2.0 1-2 Control Banding
17 EGRET 2.0 2-3 Quantitative Exposure Assessment
18 Dermal Advanced Reach Tool (dART) 2-3 Quantitative Exposure Assessment
19 Stoffenmanager 8.3 2-3 Control Banding / Risk Management
20 ConsExpo 3 Physical modelling / Quantitative Exposure Assessment
21 SprayExpo model 2.3 3 Physical modelling / Quantitative Exposure Assessment
22 Advanced REACH Tool v. 1.5 2-3 Quantitative Exposure Assessment
23 ECETOC TRA v3.1 1-2 Control Banding
13 Nano-specific
tools
10 Conventional
tools

9. • Scope analysis: mapping of input and output parameters,
examination of the intended application domain in terms of
scenarios and routes of exposure
• Accessibility and support examination: information on user-
interface and availability of input parameters required by
models/tools. Difficulty score (1-5) based on interface,
accessibility, inputs/outputs and guidance
• Sensitivity testing evaluated how an input change affects the
model output
Part I

10. Part I
nº Model Tier Model Type
1 ISO/TS 12901-2:2014 CB nanotool v1.0 1 Control Banding
2 BIORIMA (Occupational exposure section) 3 Quantitative Exposure Assessment
3 ENAETool (CPSC ENP Model) v1.0 3 Quantitative Exposure Assessment
4 LiCARA nanoSCAN v1.0 1 Risk Benefit
5 NanoSafer v1.1β 2 Control Banding / Risk Management
6 GUIDEnano tool 3 Risk Assessment / Risk Management
7 SUNDS 3 Risk Assessment / Risk Management
8 Swiss Precautionary Matrix v3.0 1 Risk Categorization
9 Stoffenmanager Nano v1.0 2 Control Banding / Risk Management
10 ConsExpo Nano 3 Physical modelling / Quantitative Exposure Assessment
11 RISKOFDERM 2 Quantitative Exposure Assessment
12 MEASE2 2.0 1-2 Control Banding
13 EMKG Expo tool 2.0 1-2 Control Banding
14 Stoffenmanager 8.3 3 Control Banding / Risk Management
25 Advanced REACH Tool v. 1.5 3 Quantitative Exposure Assessment
• Selected tools for Performance Testing (Part II)
10 Nano-specific
tools
5 Conventional
tools

11. Part I
• Reasons for exclusion:
Improved or more suitable tool already included for assessment
(e.g ConsExpo and ConsExpo nano)
Tool or user interface not available (e.g. dART)
Output variation with input variation not consistent

12. Part II

13. Part II
Collection of case studies with comprehensive information and high
quality data
126 cases
Real data
Model INPUT
Predicted data
Model OUTPUT
Tool
Real exposure data
vs.
Predicted data

14. Part II
Quality score (> 0.7):
• Relevance, reliability and completeness
Follow the existing minimum criteria to assess the tool prediction
(adapted from Fransman, Marquart and le Feber, 2009):
• Minimum 25 comparisons: real data vs. model predicted data
• Exposure situations used for assessment are widely spread over the applicability domain of the model
and evaluation is done separately
• The Spearman correlation between model estimates and measured exposure values is at least 0.6
• There are no domains of the model where exposure measurements are clearly and consistently higher
compared to the model estimates
• Measurements do not exceed the model estimates for more than 10%

15. Spearman correlation
Spearman correlation > 0.6
Part II

16. Ratio modelled/measured concentrations
Modelled > Measured
Modelled < Measured
Part II
- Less than 10%
- More than 10%

17. Part II
1E+1
1E+2
1E+3
1E+4
1E+5
1E+6
1E-5 1E-4 1E-3 1E-2 1E-1 1E+0 1E+1
Measured
particle
number
concentration
(#/cm
3
)
Nano dimensionless output (#)
1-low 2-average 3-high
Additional tool-specific assessments
Control banding tool:
Is the tool allocating higher
exposures to higher bands?

18. Part II
Additional tool-specific assessments
Risk management:
Is the tool modelled output
after recommended risk
management measures
applied lower than the OEL?

19. NA: not applicable.
All: all domains; H: Handling domain; S: Spraying domain or Leak point source; A: Abrasion domain.
* Particle number concentration.
Model
Number of
comparisons
Spearman correlation
(All / H / S / A)
< 10% of total cases
under predicted
Potential to be use for
nanomaterials?
ISO/TS CB nanotool v1.0 >25 0.63* / NA / NA / NA YES Suitable with comments
BIORIMA >25 0.84 / 0.80 / 0.31 / NA YES Suitable with comments
Stoffenmanager Nano v1.0 >25 0.78 / NA / NA / NA NA Suitable
ENAETool (CPSC ENP Model) >25 0.63 / 0.61 / 1.0 / NA
NO (10.7% and 18% when
LC applied)
Suitable with comments
LiCARA Nanoscan v1.0 2 NA NA Suitable
NanoSafer CB v1.1beta
(original and “simplified” version) >25
Original: 0.72 / 0.81 / 0.40 / NA
“Simplified”: 0.72 / 0.81 / 0.40 / NA
Original: YES
“Simplified”: NO (13.3%)
Suitable with comments
GUIDEnano 25 0.87 / 0.96 / 1.0 / NA NO Suitable with comments
SUNDS NA NA NA
Tools included in the system
analyzed independently
Swiss Precautionary Matrix v3.0 23 NA NA Suitable with comments
ConsExpo Nano 5 NA YES Suitable with comments
Nano-specific tools
Part II

20. NA: not applicable.
All: all domains; H: Handling domain; S: Spraying domain or Leak point source; A: Abrasion domain
* Not background subtracted measured concentrations used.
Conventional tools
Part II
Model
Number of
comparisons
Spearman correlation (All / H / S / A)
< 10% of total cases
under predicted
Potential to be use for
MNM?
RISKOFDERM 16 NA / 1.0 / 0.4 / NA NO Suitable for indicative use
MEASE2 2.0 >25 0.40 / 0.49 / 0.35 / 0.87 YES NO
EMKG 2.0 >25 -0.54 / -0.25 / NA / NA YES NO
Stoffenmanager 8.3 >25
Inhalable: 0.44* / 0.49* / 0.24 / NA
Respirable: 0.16* (0.18) / 0.73* (0.51)/
-0.04* (0.62) / 0.73*
NO NO
ART v1.5 >25 0.51 / 0.51 / NA / NA NO NO

21. Policy implications and next steps
Policy implications of the work:
Regional and National individual authorities may consider the tools assessed in this
study as potential methods to support nano-specific regulatory decision making
Next steps:
 Ongoing projects can use the legacy of this project
• Guidance on the use of occupational exposure models
• Generate (measured) exposure data for further evaluation of models
• Identify factors that can be measured to determine and evaluate exposure such
as measurement needs, instrumentation needs
 Assessment of user variability

22. Summary
Qualified tools:
Only 4 tools passed the test according to defined acceptance criteria
A total of 10 tools could be accepted considering different awareness comments
Where we are at and what is needed:
Step towards acceptance of tools at regulatory level, which is highly needed
Further work needs to be done on the use of occupational exposure models

23. Summary

24. Summary

25. • OECD secretariat
• Projects that provided support
• Organizations and experts that provided comments and support
Acknowledgements
FFIKA - Focused Research Effort on
Chemicals in the Working Environment,
from the Danish Government

26. THANK YOU FOR YOUR
ATTENTION
QUESTIONS AND COMMENTS?