Harmful substances in hearing protectors

Project No. BIA 4111


completed 12/2004


The function of hearing protectors is to protect the wearer against harmful exposure to noise. Results of tests performed by ÖKO-TEST magazine triggered concerns among users that this protection might be obtained at the cost of exposure to a different health hazard: harmful substances in ear plugs. At the beginning of 2002, ÖKO-TEST subjected eleven products to analysis. The result: three products contained such high levels of harmful substances that the publication regards its verdict of "inadequate" as an understatement (March 2002). The products falling foul of the tests performed by ÖKO-TEST have in some cases been in use for several decades. Manufacturers are however required under the EU type examination to issue a declaration that the parts of the personal protective equipment (PPE) coming into contact with the user's skin are not known to cause skin irritation, allergic reactions, or other health hazards. Occupational physicians responsible for care of the products' users have not reported any problems experienced by users before now which could be attributed to harmful substances in the hearing protectors.

Many employees in noise zones were nevertheless sufficiently concerned for them to choose not to use certain hearing protectors or even hearing protection at all. Reports were also received of large German companies withdrawing certain ear plugs from use. The result was the reappearance of a familiar but avoidable hazard at high-noise workplaces: the potential development of noise-induced hearing loss.

The only remedy in this emotionally charged situation were objective data and comprehensible assessments - which did not exist. The objective of all activities within this project was the replacement or, should that not be possible, reduction to the lowest absolutely essential level of the substances in hearing protectors suspected of impacting negatively upon the health of users.

Hearing protectors which do not violate the maximum concentrations required by the BG expert committee personal protective equipment (FA PSA) were to be awarded a BG-PRÜFZERT mark for their low harmful substance content.


The FA PSA responded immediately to the specific situation in plants. As soon as the report had been published in ÖKO-TEST, the committee formed, with the support of the BG Institute for occupational safety (BGIA), a task force composed of OS&H professionals and hearing protector manufacturers. Chemists were undertaking to develop reliable analysis methods as quickly as possible, such methods not previously being available or validated for hearing protectors. Toxicologists were compiling data on internationally recognized permissible maximum concentrations for substances from all possible product groups in order to extrapolate permissible maximum concentrations for substances in hearing protectors which reflect the current state of scientific findings. They also developed a test for assessment of the overall toxicity for such parts of hearing protectors which come into contact with the wearer's skin. Hearing protector material supplied by the manufacturer was tested by a number of laboratories in round-robin tests for its total metal content, organic tin compounds, and phthalates. The objective was to identify the standard analytical methods yielding results with the greatest degree of comparability. These methods may form the basis of the planned test mark.


Round-robin tests were performed by four analytical laboratories for selected substances; the detection methods used were specified, and differed from one laboratory to the next. The experience gained with these round-robin tests was used for proposals of suitable analysis methods and quality criteria. The levels of the individual limit values were defined by the PPE BG expert committee with the support of BIA experts and in consideration of the state of the art. Issues concerning analysis, technical feasibility and toxicology were also considered. Draft test principles for issuing of the BG-PRÜFZERT mark which govern the harmful substance content of hearing protectors have been available since December 2004.

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Financed by:
  • Hauptverband der gewerblichen Berufsgenossenschaften (HVBG)
Research institution(s):
  • Berufsgenossenschaftliches Institut für Arbeitsschutz - BIA
  • BG-übergreifend

-cross sectoral-

Type of hazard:

Lärm/Vibrationen, Gefahrstoffe


Persönliche Schutzausrüstung, Lärm, Prüfverfahren

Description, key words:

harmful substances, hearing protectors, ear plugs, metals, organic tin compounds, softeners, low pollutant hearing protector