Web links, documents and free of charge tools

Use the documents and tools listed below for the qualitative and quantitative, occupational exposure risk assessment.
They are grouped in the following Click-and-go headers:
1. Exposure assessment and compliance testing strategies
2. Sampling and analytical methods
3. Exposure databases
4. Occupational Exposure Limit Values (OELV)
5. Compliance testing statistical tools
6. Lognormality and exposure variability
7. Compliance for mixtures
8. Exposure modeling
9. Chemical identification, physchem properties and hazard information.

For Specific Dutch tools click here (in het Nederlands).


1. Exposure assessment and compliance testing strategies
Current days, workplace exposure assessment is described in different public available, free of charge documents:

Not free of charge, but recognized standards are:
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2. Sampling and analytical methods
Free of charge sources with measurement methods are: 3. Exposure databases
For prior knowledge on substance workplace air exposures (raw and aggregated data), consult: 4. Occupational Exposure Limits Values (OELV)
As a license to operate and to test workplace air compliance, an employer needs to have an OELV for all chemicals to which workers are exposed at his premises or under his responsability. There are many (inter)national systems that provide OELV's OELVs differ in goal and quality and should therefore be chosen carefully. For more information on the hierarchy of OELV's see Presentation on H3##-statement based kick-off levels. Bilthoven NVT-AT 140925
Below OELV sources are presented in groups of different hierarchy.

4.1 Unbiased health based only OELV's
"Health based only" means that no political, socioeconomic and technical feasibility factors have influenced the value (level & duration) of the OELV. Unbiased means not established or financed by interest groups. Documents published before 1997 may suffer from limited quality control and transparancy. The web sites below contain several hundreds of OELV documents often, however, on the same chemical substances. The OELV's proposed for the same chemical substances may differ in value, reflecting differences in scientific sources used, different hazard assessment techniques (i.e. safety factors used) and differences in hazard perception. Compliance with these limits may safeguard the employer from liability for health claims. 4.2 Health/Toxicology based
For the OELVs below the independency from interest groups and/or unbiased science is not guaranteed.

4.3 Some regulatory OELV's in the EU

Most countries have regulatory limits. Non-compliancy may lead to a penalty.
If socio-economical feasebilty has lead to a level that exceeds the health based level, then compliance with the regulatory limit will not safeguard the employer from liability if exposure exceeds the health based OELV
  • EU Binding occupational exposure Limit Values.
  • EU Indicative Occupational Limits Values. adopted as regulatory limits in most EU countries.
  • Germany TRGS 900.
  • UK EH40/2005 Workplace exposure limits. Table 1 WEL (air). Table 2: Biological monitoring guidance values (BMGVs)
  • France valeurs limites d'exposition professionnelle (VLEP) indicative (VL), binding indicative (VRI) or binding restricted (=réglementaires contraignantes) (VRC).
  • Netherlands Cumulative list of legal limits (in Dutch)
  • Belgium KB Chemical agents.
  • Italy legislation for OELV.
  • Norway Limit values.
  • Sweden OELV's.


  • USA legal OELV's
  • OHSA-PEL The federal OELV's, different states like Texas and California have there own OELV's.


  • 4.4 Data-poor substances
    While the sources under 4.1 through 4.3 mainly contain OELVs for the limited number of data-rich substances, most substances do not have an OELV, due to the lack of sufficient and relevant high quality human health & toxicology data.
    However if GHS or CLP health H3##-statements are known, Kick-off levels can be established.
    H3##-statements to derive a Kick-off can be found in the ECHA database with hazard classification and labeling information for all harmonized (6000) and notified (>100,000) dangerous substances in the EU.
    Kick-off levels are used as a conservative starting point for compliance testing.
    A guidance for setting occupational exposure limits for data-poor substances has been developed by ECETOC, see TR-101

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    5. Free of charge compliance testing statistical tools (downloads) 6. Lognormality and exposure variability
    Based on observations in different countries and many situations (Oldham UK 1953, Coenen GE 1966, Leidel US 1977) it is widely accepted that the body of the workplace air exposure distribution is well represented by the lognormal distribution. In the tails of the exposure distribution the lognormal distribution may not fit: it can predict non-existing or non-realistic concentration probabilities exceeding physicochemical limitations like maximum dustiness for airborn solids, the atmospheric pressure for a gas and the saturation concentration for vapours. It can also predict (annual) frequencies of exceeding safety bariers like the visus limitation of inhalable dust (>10 mg/m3) (which may occur) or the explosion concentration (LEL) of gas and vapours, which hopefully will not occur.
    The Geometric Standard Deviation (GSD) is the descriptive statistic for the variability (=dispersion) of the lognormal distribution and used for the extrapolations in the tails.
    The GSD is:
  • the antilog (=EXP) of the standard deviation (s) of the logarithms of the results EXP(s)
  • the unbiased estimator of the population GSD [EXP(σ)] with minimum variance, meaning the most efficient estimator with an expectation equaling the population EXP(σ), meaining that the GSD equals EXP(σ) on the average for every sample size.
  • by definition lager than one plus the analytical coefficient of variation (1+CVt) (NIOSH 77-173 p124) .
  • considered to be an intrisic property for every substance/Similar Exposure Group(SEG) combination or its REACH equivalent the workers task/activity Contributing Scenario t-CS.


  • The numerical value of GSD in a SEG/t-CS depends on workplace factors / operational conditions like :
  • the the number of different tasks/handlings included and sequentially performed during the observation period (task, shift and/or the working week),
  • in- or outdoor,
  • industrial or professional setting
  • technical and organisational risk management measures (ventilation, instruction etc),

  • But also on:
  • the way workers do their job (between worker differences),
  • environmental factors and
  • Global positioning and altitude; climat and its variability througout the year.

    In well performed exposure assessments low GSDs may occur in:
  • highly controlled indoor workplaces, clean rooms etc.
  • REACH t-CS, assessing a single combination of Operational Conditions (OC) and Risk Management Measures (RMM) in industrial use
  • SEG's of workers performing only a single-task at a fixed workplace
  • workplaces with a relatively high constant background that camouflage all spatial and temporal variability of workers activity


  • Representative TWA8 hours measurements in well-defined SEG's and well performed sampling plans may show GSD's up to 14.
    See in example BOHS Conference 2013, GSDs in the real world and The distribution of long-term GSD's in chemical industry SEG's (in Dutch , English summary).
    Tielemans (2008) established default dispersion factor for liquids and solids based on a small but high quality database: From this it is derived that the corresponding default GSDB+W for solid=5.4 and for liquid GSDB+W=8.2. These GSDs may even be too low as 0.5*LOD was used for the non-detectables.

    AIHA's IHStat states that GSD>3 indicates "process out of control or poorly defined groups". IHStat lacks however to indicate that its two noncompliance statistics perform badly at GSD>3 and sample size beteween 2 and 6. see above
    In contrast, low level GSDs can indicate "poor sampling strategy" or "poor data handling" caused by:
  • small sample size underestimating the GSD
  • sampling on one or a few consecutive days (auto-correlation)
  • sloppy handling of non-detectables
  • 2-decades analytical detection methods (like gravimetric dust and inorganic acid)
  • using EM in stead of PAS
    On the other hand, in a clean room and other situations where one would expect a low GSD, at value at or above 1+CVt may indicate suboptimal controls or bad technical sampling and/or laboratory handling.

    Low GSDs occured also in the ancient industrial hygiene era:
  • when workers in process industry and assembly lines performed a single task during a whole shift,
  • with high background levels camouflaging the variability of workers activity,
  • when sampling techniques were insensitive, and
  • when officers in charge forbid their industrial hygiene sergeants to report GSD>2.

    Industrial Hygienist are therefore advised, before testing compliance, to compare the GSD found with an expected value, using:
  • measurement series performed before
  • GSDs reported in large exposure databases
  • Read across with comparable substances and workplaces
  • Modeling, if possible
  • Physical-Chemical properties

  • Tools to calculate and compare GSD's, and to test the Lognormal goodness-of-fit can be found in 5. Compliance testing statistical tools
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    7. Compliance for mixtures
    There are several methods for compliance testing of mixtures in the workplace air: The three methods above imply, that the appraiser samples all components in the mixture. Another approach for vapors with comparable effects is to select the most critical component (based on the saturation concentration and the OELV) and to adjust its OELV to the composition of the mixture in the air. XLUNIFAC is the method of preference. The methods above do not include synergy or antagonism, the phenomena that the toxicokinetics and/or -dynamics of the health effects change due to the interaction of the components in the mixed exposures
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    8. Exposure modeling
  • TREXMO (TRanslation of EXposure MOdels) integrates six commonly used occupational exposure models: ART v.1.5, STOFFENMANAGER® v.5.1, ECETOC TRA v.3, MEASE v.1.02.01, EMKG-EXPO-TOOL and EASE v.2.0.
  • AIHA Tools and Links for Exposure Assessment Strategies
  • Chesar
  • Advanced REACH Tool
  • Stoffenmanager
  • SkinPerm Estimates the flux and the quantity penetrating the skin from the air or from a liquid/solution in contact with the skin
  • UPERCUT A hazard identification tool for toxic risk following dermal penetration of chemicals
  • IndusChemFate
  • EPA exposure modeling
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    9. Chemical identification, physchem properties and hazard information
    ECHA's Information on Chemicals with the REACH and CLP information on >100,000 substances used in the EU. Check every EU Safety Data Sheet (SDS) or the harmonized classification information using this site on recent changes
    GESTIS-database with nearly 10,000 substances, including information on occupational chemical loads without an EU SDS obligation, like welding fumes or wood dust
    IARC Monographs Evaluation of Carcinogenic Risk to Humans
    Health Council of the Netherlands Evaluation of the carcinogenity, genotoxicity and reprotoxicity, including non-REACH substances
    Dohsbase contains substance identity information of >260,000 chemicals, health hazard information of 110,000 and physchem information of 40,000 substances
    NIOSH Pocket Guide to Chemical Hazards
    Safe work Australia

    Useful free of charge physchem online databases are:
    eChemPortal. A public web site with information on chemical properties. ECHA is a key collaborator in the development of the OECD physchem software and hosting
    ChemIDplus Advanced. A TOXNET® (TOXicology Data NETwork) database from the US National Library of Medicine covering chemicals and drugs
    NIST Chemistry WebBook. The US National Institute of Standards and Technology (NIST)
    FatePointer . The US SCR Syrres subsstance properties databases
    EPI Suite is not only a large database with measured physchem data but also with physchem estimates based on the SMILES code.
    ToxCast™ Data Chemical details for 8,599 unique substances (GSIDs) and DSSTox standard chemical fields (chemical name, CASRN, structure, etc) for EPA ToxCast chemicals and the larger Tox21 chemical list
    ChemBioFinder.com The CambridgeSoft chemistry and biology reference database
    Chemspider
    Chemicalize

    Useful free of charge toxicological databases are
    ATSDR Toxic Substances Portal
    TOXNET Hazardous Substances Data Bank (HSDB)

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    Specifiek Nederlands
    Zelfinspectie I-SZW. In vier stappen beoordelen of uw bedrijf gezond en veilig werkt met gevaarlijke stoffen volgens de Arbeidsinspectie
    Databank Grenswaarden Stoffen op de Werkplek van de Social Economische Raad (SER-GSW) met Europese werkplek atmosfeer grenswaarden en REACH DNELs.
    Veilig werken met chemische stoffen.nl Door de sociale partners binnen de SER ontwikkelde leidraad voor het veilig werken met chemische stoffen.
    Hiermee is het gat gedicht ontstaan na het afschaffen van de meeste wettelijke en bestuurlijke MACs in 2007. Het bevat ook de goede praktijken die in de afgelopen decades zijn ontwikkeld door bedrijven en branche verenigingen.
    DOHSBase Database met het grootste en hierarchisch opgebouwd bestand aan grenswaarden en meetmethoden
    AI interne instructie toetsen van de meetresultaten aan luchtgrenswaarden (2007).
    Kennisdossier Gevaarlijke Stoffen Tot stand gekomen door multidisciplinaire samenwerking tussen de beroepsverenigingen van arbeids- en organisatiedeskundigen, bedrijfsartsen, arbeidshygiënisten en veiligheidskundigen

    NVvA en Arbo-pagina
    Wil je meer weten over de Arbeidshygiëne in Nederland dan zoek dan op de webstee van de Nederlandse Vereniging voor Arbeidshygiëne. Voor Arbo in het algemeen is er de Startpagina dochter Arbo

    De website van de Belgische Arbeidshygiene vereniging BSOH ontsluit een groot aantal pratische tools

    SKINPERM
    Bij de beoordeling van de blootstelling is voor veel stoffen de bijdrage van de opname via de intacte maar onbeschermde huid belangrijk. Van de homepage van Wil ten Berge is het freeware programma SKINPERM te downloaden dat op grond van een aantal fysisch chemische parameters de potentiële huiddoorlatendheid van een gas, damp of een vloeistof schat. En met aanvullende gegevens over kleding, besmet oppervlak e.d. wordt de mogelijke opname in het lichaam geschat. Een goede aanvulling dus op NEN 689 die volledig op de werkplekatmosfeer is gefocust.

    U vindt dit programma door te surfen naar http://home.planet.nl/~wtberge/

    SKINPERM schat de hoeveelheid van een chemische stof die via huid in het lichaam wordt opgenomen indien het agens:

    De opname van vaste stoffen en aerolsolen is niet met SKINPERM te schatten.

    Patchwork
    Paul Schepers, wetenschappelijk onderzoeker bij de Universiteit Nijmegen, heeft het zoeken naar toxische eigenschappen van chemische stoffen op het internet wel zeer gebruiksvriendelijk gemaakt. Zijn afloopschema Patchwork leid je naar de meest betrouwbare, publiek vrij toegankelijke, databestanden.