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Hazardous Substances

Published: 10th Jan 2006


Health and safety at work is important for humane, social and economic reasons, and is in the interests of both employer and employee. This is particularly true with regard to contact with hazardous substances; at international level the "Code of Practice on Safety in the Use of Chemicals at Work" (1993) set out by the ILO should be observed.

Hazardous substances are employed in virtually all industrial plants. When asked about the hazardous substances in use in their plants, however, employees are frequently found to have insufficient awareness of dealing with them. Opinions on what substances are hazardous are frequently unclear, incorrect, and in many cases hair-raising. An answer frequently heard is that hazardous substances are substances and preparations marked with an orange hazard symbol. This is a correct but by no means comprehensive answer.

What are hazardous substances?

Within the European Union (EU) the concept of hazardous substances (hazardous chemical agents) is defined in 98/24/EC of 7 April 1998 on the protection of the health and safety of workers from the risks related to chemical agents at work. It is explained in somewhat greater detail below.

  • Hazardous substances are chemical agents classified as 'dangerous substance' according to the criteria of Directive 67/548/EEC Annex VI (excluding substances which only pose a hazard to the environment) and which accordingly exhibit at least one of the following hazard characteristics: explosive, oxidising, extremely flammable, easily flammable, flammable, very toxic, toxic, harmful, corrosive, irritant, sensitising, carcinogenic, mutagenic or reprotoxic
  • Hazardous substances also include preparations which meet the criteria for a 'dangerous preparation' according to Directive 88/379/EEC (excluding preparations which only pose a hazard to the environment)
  • Artificial ageing using a powerful xenon lamp

These substances are generally marked with the hazard symbols shown opposite. There is one exception: flammable substances and preparations do not bear an orange flame symbol, but are marked only with the R phrase 'Flammable'.

  • Finally, hazardous substances also include all chemical agents which owing to their physical, chemical or toxicological properties and the manner in which they are employed at the workplace pose a risk to the health and safety of employees. These include: - all substances subject to a workplace limit value, regardless of whether they are marked with hazard symbols or R phrases; - substances which are not classified as explosive, but which may form explosive mixtures when mixed with air (such as coal dust when raised)

These potential hazards do not result in marking with a hazard symbol or R phrase.

A glance at the hazard symbol is therefore clearly insufficient for identification of all substance-related hazards. Further information can be obtained either from the material safety data sheet of the product concerned, or from relevant databases.

The GESTIS database on hazardous substances

The GESTIS database contains all information required for the identification of substance-related hazards and for taking of the necessary safety measures. It differs from other databases in particular in the following ways:

  • It contains comprehensive information on intake routes, on the mode of action of the substances upon the human body, and also on first aid; furthermore, this information is provided in a form comprehensible to the layman. This body of data is unique in its breadth and depth, and is continually updated
  • The statutory provisions governing the individual substances are presented in condensed form and are continually kept up to date
  • The instructions for safe handling are significantly more comprehensive than the information provided on material safety data sheets. The technical, organisational and personal measures which ensure safe handling of the substances are described. Suitable (and unsuitable) protective measures are also described for hazard incidents (fire, spillage, gas leakage)

Work on creation of the GESTIS database on hazardous substances, which was originally called the 'central substance and product database' began in 1986. It was renamed the 'GESTIS database on hazardous substances' in 1999, when unrestricted access to all content was made available to the public over the Internet.

Information provided by the GESTIS database

The home page at provides a brief description of the database and informs visitors of the terms of use and of means of contact. A FAQ (list of frequently asked questions) is provided, together with an example of a substance data sheet, and a link to the "guest book".

The "open English version" button calls up the search form, which offers two modes of access to the substance data sheets.

The "Search" function can be used to perform a search by the name of the substance, its ZVG number, CAS number, EG (EU) number or INDEX number. Full-text searches can also be performed for any desired term. Should only one hit be returned, the data sheet concerned is displayed directly in the right-hand window; otherwise, a list of hits is displayed from which the desired document can be selected.

The substance data sheets contain comprehensive information (including structural formulae) for the identification and characterisation of substances, comprehensive physical and chemical data, possible hazardous chemical reactions, comprehensive occupational health information (intake routes, modes of action), information on first aid, on safe handling of the substances (e.g. protective measures, hazard incidents, disposal), and also the regulations applicable to the substance in question. An overview can be obtained quickly of the current hazard classifications, workplace limit values, water pollution classes, and numerous other regulations. The hazard classifications indicated include not only the EU classifications but also, for substances without EU classification, the manufacturers' classifications which correspond most closely in consideration of the available data.

The occupational health and first-aid information is not yet available in full in English. It will be translated into English when the data record is next updated.

The individual sections are structured as web pages in their own right, at the bottom of which links are provided to other subject areas. The information can be printed out by a click on the printer symbol above the display window. Content can also be marked and copied via the clipboard into other documents.

Example: Data on personal protection equipment against dichloromethane

The example on page 78 shows that the data in the GESTIS substance database are considerably more comprehensive than those available from traditional sources. Material safety data sheets in particular are often deficient in providing only limited information. Section 8 of material safety data sheets, Exposure Controls/Personal Protection', for example, frequently contains the information 'Hand protection: Yes' or 'Hand protection necessary', despite the requirement of the European directive governing material safety data sheets that the type of protective glove used during handling, including the material of the glove and its penetration time, are to be indicated with reference to the level and duration of skin exposure. It must be considered that the penetration times indicated in the GESTIS hazardous substance database are not to be regarded as equal to the wearing times, as the former are established under standard conditions (22 °C, material not stretched). Under actual conditions, the warmth from the hands and stretching of the glove may lead to the penetration times being reduced. Furthermore, the information applies to the substance in its pure form only, and not to solutions or mixtures involving other substances.

Under the European directive, suitable breathing masks and filters should be stated in the same section of the material safety data sheet. Generally, however, the sheet simply states that type-tested breathing masks must be worn in unventilated areas and/or during work in areas in which the threshold limit values (TLV or German MAK) are exceeded.

This incomplete information is particularly dangerous in the case of materials which present acute hazards to users that are not directly evident from the classification and marking. This is the case for example with dichloromethane. This substance is one with a low boiling point, and has a very high vapour pressure even at room temperature. Dichloromethane is classified by the EU as a suspected carcinogen. Dichloromethane vapour has a narcotic effect, leading relatively quickly to irreversible damage and death. If dichloromethane is used openly and over a large area, its high volatility almost always results in the workplace limit value being exceeded in the atmosphere.

Numerous occupational accidents have already occurred in which workers lost consciousness after only 30 minutes because they wore no or inadequate personal protective equipment.

The GESTIS hazardous substance database contains all essential information relating to PPE for protection against dichloromethane. It states for example that the AX respiratory filter indicated may be employed only in cases of exposure to the pure substance. As soon as dichloromethane is present in combination with other substances (for instance in stripper products), a respiratory protective device must be worn which is not dependent upon the ambient air, as the filter no longer provides protection in this case. The same applies in the case of concentrations which exceed the maximum application concentration of the filter, and with oxygen concentrations below 17% volume.

By way of example, the information on personal protective equipment for use with dichloromethane as indicated in the GESTIS hazardous substance database is provided.


Body protection: Depending on the risk, wear a tight, long apron and boots or suitable chemical protection clothing. The protection clothing should be solvent resistant.

Respiratory protection: In an emergency (e.g.: unintentional release of the substance, exceeding the air threshold limits) respiratory protection must be worn. Consider the maximum period for wear. This is a low-boiling-point substance of group 1 of the BGR 190. Respiratory protection: Gas filter AX Colour code: brown Max. concentration for use: 100 ml/m3 for max. 40 min. 500 ml/m3 for max. 20 min. Filters may only be used in their original condition. Repeated use is permissible for the appropriate maximum period within a single shift (max. 8 hours). Do not use AX filters against mixtures of low-boiling-point substances and other organic compounds. For more details, consult the 'Regeln für den Einsatz von Atemschutzgeräten' (BGR 190).

Respiratory protection: insulating device Use for concentrations above the usage limits for filter devices, for oxygen concentrations below 17% volume, or in circumstances which are unclear.

Eye protection: Sufficient eye protection should be worn. Wear glasses with side protection. If the eyes may potentially come in contact with the liquids, then chemical safety goggles are necessary.

Hand protection: Use protective gloves. The glove material must be sufficient impermeable and resistant to the substance. Check the tightness before wear. Protect the skin. Gloves should be well cleaned before being removed, then stored in a well ventilated location. Textile or leather gloves are completely unsuitable.

For protection against spray or splash (brief contact), protective gloves of the following materials are suitable: Fluoro carbon rubber - FKM (0,4 mm) Glove (multi-layer) - PE/EVAL/PE (PE=Polyethylene; EVAL=Ethylene-vinyl-alcohol-copolymer) Following materials are unsuitable for protective gloves: Natural rubber/Natural latex - NR Polychloroprene - CR Nitrile rubber/Nitrile latex - NBR Butyl rubber - Butyl Polyvinyl chloride - PVC

Skin protection: Skin protection is necessary.

Apply water-soluble skin protection preparations to the clean skin and thoroughly rub it in before beginning work and after each break. Skin protection preparations cannot replace any safety gloves. The skin must be washed with soap and water before breaks and at the end of work. Methylene chloride must not be used for the cleaning of skin. Apply fatty skin-care products after washing.

Industrial hygiene: Foods, beverages, and other articles of consumption must be stored in such a manner that they cannot come into contact with the hazardous substance. Special designated areas are for these purposes. Avoid contact with skin. In case of contact wash skin. Avoid contact with eyes. In case of contact rinse the affected eye(s). Avoid inhalation of vapour. In NO case drink alcohol. Avoid contact with clothing. Contaminated clothes must be exchanged and cleaned carefully. Provide washrooms with showers and if possible rooms with separate storage for street clothing and work clothing.

Access to the GESTIS database on hazardous substances

Since the Internet launch of the German version in 1999, public awareness of the database has continually increased. Immediately following the database's launch, it was accessed a little over 1,000 times per month. This figure rose to almost 60,000 queries per month by the beginning of 2005. A similar trend can be seen for the English version, which has been available on the Internet since 2002; the number of visits remains lower, but is continually rising.


Links to the database should ideally point to the home page with the alias address, as this URL will not be affected by any internal changes to the access address.

Links can also be created within other parties' web sites to particular data sheets in the GESTIS hazardous substance database. In this case, the link should point to:

This link causes the relevant substance to be queried in the database and loaded into the frame on the calling page. The number 010110 with the grey background is the unique identifier of a substance within the GESTIS hazardous substance database (ZVG number). It can be substituted with any other valid ZVG number (always six digits, with leading zeros if applicable).

Users of the GESTIS hazardous substance database

Users of the GESTIS hazardous substance database range from plant safety professionals, teaching staff and students at universities and other research institutions, through company physicians, first-aiders and rescue service personnel, to the officials at the BGs and the factory inspectorates. Private individuals also make considerable use of the GESTIS database on hazardous substances. These parties are all supported by GESTIS on a daily basis in their search for relevant information for the most diverse of problems. Some examples:

  • Employers and safety engineers use the database for research into the hazardous properties of chemicals, for example for the purpose of risk assessments. It provides them with information on the safe handling of hazardous substances, the applicable personal and engineered protective measures, and the emergency measures to be taken in the event of fires and accidents
  • Occupational physicians consult the database in order to find information on preventive health monitoring, the making ready of suitable antidotes, and suitable first-aid measures for cases of accidents and poisoning
  • Fire services find information on fire and explosion properties and on suitable extinguishing agents
  • Public authorities research for instance whether precautionary measures are obligatory for certain substances or whether constraints are imposed upon their use
  • Schoolteachers, college lecturers and students find information in GESTIS on potential risks associated with the handling of hazardous substances (e.g. in the context of work experience) and are able at the same time to become familiar with the substances concerned
  • Finally, GESTIS is useful to private individuals, who can use it for example to find the properties of hazardous constituents of household products, or to learn the significance of hazard symbols on packaging

This wide group of users shows that in the area of hazardous substances, GESTIS is a suitable response to the issues thrown up by the increasing complexity of working life, and that it provides its users with access at all times to detailed and up-to-date information.

Dialogue with users

A 'guest book' offers users the opportunity to communicate their suggestions, ideas and comments. The 'guest book' may however be unsuitable for the communication of certain issues or problems. For such cases, a special e-mail address has been set up. Questions relating to hazardous substances which are sent to this address are relayed directly to members of the GESTIS team.

Author Details:

T. Smola, J. Cramer, J. Riedel and A. Veloso-Schneider

BG-Institute for Occupational Safety and Health - BGIASubdivision 'Information on Hazardous Substances',D-53754 Sankt Augustin, Germany


Published: 10th Jan 2006 in Health and Safety International

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