This year the new criteria for the assessment of contact and inhaled allergens deserve particular notice. These new criteria are based on a variety of information sources for which a graded evaluation of their degree of evidence was performed. In this way, a significant improvement regarding the reproducibility and uniformity of allergen evaluation was achieved. The criteria have the character of guidelines and serve as a guide to a logical evaluation of the data. However, in special cases deviations from their strict application are possible.
Furthermore, the aerosol section was revised by adapting it to the current terminology in this field.
Based on epidemiological data, beryllium and its inorganic compounds have been classified as carcinogenic in humans and, therefore, were placed in carcinogenicity category 1. The mycotoxin ochratoxin A was proven to be carcinogenic in animal experiments and classified in carcinogenicity category 2.
The irritant gas and "familiar" environmentally harmful agent nitrogen dioxide was assigned to carcinogenicity category 3B as a suspected carcinogen and the previous MAK value was suspended because of genetoxic activity. The commission recommends setting a much lower threshold value for industrial safety than the 5 ppm that have applied so far.
In the course of examining suspected carcinogens in category 3 by establishing categories 4 and 5, the solvent tetrahydrofuran was reclassified in category 4 but the previous MAK value of 150 mg/m³ remains. Rhodium and inorganic rhodium compounds as well as bromochloromethane – a compound with a similar structure as the recently re-evaluated dichloromethane – were classified in category 3B as suspected carcinogens. A mutagenic effect on germ cells or a suspicion of such an effect must be expected for 4-chlor-o-toluidine, ethylene imine, ochratoxin A, and epichlorohydrin.
The BAT value of lead for women of childbearing age was reduced to 100 µg lead/l blood. This relatively low value is determined by the background exposure of the general population.
For five substances MAK values changed or new ones were proposed, and in two cases (dimethoxymethane, tetrahydrofuran) the value was confirmed after an in- depth examination. Due to a lack of data, MAK values were not set for seven substances (alkyl ether carboxylates, dicyandiamide, diphenyl cresyl phosphate, nicotine, propionic acid, tellurium and its inorganic compounds, 6,6,6-[1,3,5-triazine-2,4,6-triyltriimino] trihexanoic acid). The re-evaluation of earlier MAK values was conducted intensively, also in close cooperation with the European (SCOEL) and the American (TLV) Commissions. It was decided to drop the MAK values for five substances (bromochloromethane, nitrogen dioxide, nicotine, propionic acid, tellurium and its compounds) due to a suspicion of carcinogenic effect or insufficient data for a health evaluation from the current perspective.
Seven working substances were also examined with respect to being particularly harmful during pregnancy. The methyl and butyl esters of chloroformic acid as well as cyclohexylamine and the pesticide cyfluthrin are placed into group C, which comprises those substances from which no harm to the embryo is anticipated if the MAK value is complied with. However, dimethoxymethane (methylal) was placed into pregnancy group D, where a risk of harming the embryo currently appears rather unlikely but cannot be ruled out with sufficient certainty. Due to a lack of data, oxalonitrile (cyanogen) could not be assigned to one of groups A to D and was included in list IIc.
There were twelve examinations or new listings for carcinogens. Beryllium was reclassified to category 1, proven carcinogens in humans. This year, ochratoxin A was classified in category 2, i.e., it should be considered carcinogenic for humans. Bromochloromethane, rhodium and its inorganic compounds, nitrogen dioxide and the formaldehyde-releasing substance 1,3,5-triethylhexahydro-s-triazine were newly entered into the category of suspected substances 3B. Tetrahydrofuran was reclassified in category 4 with a MAK value of 150 mg/m³. No suitable candidate was found this year for category 5.
This year 14 substances were examined for their respiratory tract sensitising and skin sensitising properties. New labelling was assigned to 14 chemicals, among them the compounds cinnamaldehyde, cinnamyl alcohol, eugenol and isoeugenol, which are used as fragrances. The warning "H", which signifies that percutaneous absorption may significantly contribute to work place toxicity, was newly given to 14 substances, among them the carcinogenic compounds auramine, soluble cadmium compounds, epichlorohydrin and ethylcarbamate. This warning label was checked and confirmed for five more working substances, among them nicotine and tetrahydrofuran.
There are five new entries and changes in the section "BAT values, biological guideline values and exposure equivalents for carcinogens" ("BAT-Werte, BLW und EKA"). Apart from lowering the BAT value for lead for women under 45 years of age, the BAT value for tetrachloromethane was lowered to 3.5 µg/l blood. BAT values for 1,4-dichlorobenzol, ethylbenzol and phenol were suspended because of (possible) carcinogenic properties of these substances. Biological guideline values (BLW) were suggested for phenol and the cresols.
The Senate Commission produced detailed scientific justifications for each new entry and change in the MAK and BAT value list 2003. They are published by WILEY-VCH of Weinheim and since 2002 have also been available online. Every year the examination and new entry of MAK values and the classification of numerous substances are announced in the Yellow Pages of the MAK and BAT value list.
A list with all new entries and changes is available for download at http://www.dfg.de/aktuelles_presse/reden_stellungnahmen/download/mak2003.pdf.
Notes for editors:
Editors may request a free review copy from the DFG Press and Public Relations Section, phone: 49-0-228 885-2109 or -2119, fax: 49-0-228 885-2180, email: heike.klebe@dfg.de.