ANSES publishes new recommendations for occupational exposure limits

Some workers have to breathe in chemical substances that are potentially harmful to their health. Chemical risk prevention in the workplace is based primarily on the principle of substitution (replacing a hazardous product with a non- or less-hazardous product or process) or, failing that, the reduction of pollutant concentrations to the lowest possible levels. In this context, the Ministry of Labour sets Occupational Exposure Limits (OELs) for substances that are considered to be hazardous. These threshold values correspond to concentrations in the air that should not be exceeded for a given reference period.

As part of the National Occupational Health Plan, the Ministry of Labour entrusted ANSES with providing the scientific expertise needed to set occupational exposure limits. The aim of this expert assessment phase is to recommend appropriate concentration levels (atmospheric or biological) to protect the health of workers as well as suitable measurement methods for comparing actual atmospheric occupational exposures to the recommended OELs.

In the first half of 2017, ANSES published several collective expert appraisal reports as part of this permanent mission. These reports were submitted for public consultation. The Agency's recommendations provide a basis for discussion by joint labour-management bodies under the aegis of the Ministry of Labour with a view to establishing statutory occupational exposure limits.

Recommendations for the establishment of new atmospheric limit values

The Agency is proposing atmospheric limit values based on a scientific assessment of health effects for six substances:

For trichloroethylene:

• a pragmatic 8h-OEL of 40 mg.m-3 (instead of the value of 405 mg.m-3 set by a circular in 1983) is recommended to prevent the nephrotoxicity of this substance. The aim of the recommended 8h-OEL is not to protect against the carcinogenic effects of trichloroethylene, but to provide a tool for limiting exposure levels in the workplace;
• the concentration corresponding to five times the recommended value for the 8h-OEL should not be exceeded over a 15-minute period.

For di-n-butylphthalate (DnBP):

• an 8h-OEL of 2 mg.m-3 (instead of the value of 5 mg.m-3 set by a circular in 1987) is recommended to prevent the reprotoxic effects of this substance;
• the concentration corresponding to five times the recommended value for the 8h-OEL should not be exceeded over a 15-minute period.

For butylbenzyl-phthalate (BBzP):

• an 8h-OEL of 13 mg.m-3 (no current value) is recommended to prevent the reprotoxic effects of this substance;
• the concentration corresponding to five times the recommended value for the 8h-OEL should not be exceeded over a 15-minute period.

For 2-ethoxyethanol and 2-ethoxyethyl acetate (EGEE and EGEEA):

• an 8h-OEL of 1 ppm is recommended to prevent the haematotoxicity of these substances (instead of the value of 2 ppm set by a decree in 2012);
• the concentration corresponding to five times the recommended value for the 8h-OEL should not be exceeded over a 15-minute period.

For n-butanol:

• a short-term exposure limit (15min-STEL) of 100 mg.m-3 (instead of the value of 150 mg.m-3 set by a circular in 1982) is recommended to prevent eye irritation effects.

Furthermore, a "skin" notation, indicating the need to take dermal exposure into account when assessing exposure to a chemical substance, is recommended for trichloroethylene, butylbenzyl-phthalate, 2-ethoxyethanol, and its corresponding acetate.

Regarding the recommended methods for measuring these six substances in workplace atmospheres, ANSES emphasises that no measurement methods could be recommended for butylbenzyl-phthalate.

The Agency's other work: proposal of Biological Limit Values

Since the beginning of 2017, in addition to these various recommendations for atmospheric limit values, ANSES has also recommended Biological Limit Values (BLVs) and Biological Reference Values (BRVs) to improve the monitoring of exposure in workers to hexavalent chromium and its compounds, acrylamide, di-n-butylphthalate, and benzylbutyl-phthalate.

Thus, for the biological monitoring of occupational exposure, the Agency recommends:

For hexavalent chromium and its compounds:

• a BLV for urinary chromium of 2.5 µg.L-1, or of 1.8 µg.g-1 for creatinine, corresponding to exposure to the 8h-OEL of 1 µg.m-3 for hexavalent chromium. However, as this value was established only on the basis of studies undertaken in a single type of industrial sector (chromium plating), the application of this BLV is recommended only for exposure to hexavalent chromium compounds. In the event of mixed exposure (to hexavalent and trivalent chromium) and considering the contribution of trivalent chromium exposure to concentrations of urinary chromium, urine measurements may be taken but should be interpreted in light of the respective levels of atmospheric concentrations for the various compounds of chromium;
• a BRV for urinary chromium of 0.65 µg.L-1 (or 0.54 µg.g-1 for creatinine).

For acrylamide:

• a BRV for haemoglobin adducts of acrylamide (measured in blood) of 85 pmol.g-1 for globin for non-smokers and 285 pmol.g-1 globin for smokers.

For di-n-butylphthalate:

• a BRV for urinary mono-n-butylphthalate (MnBP) of 70 µg.L-1, or 50 µg.g-1 for creatinine.

For butylbenzyl-phthalate:

• a BRV for urinary mono-benzylphthalate (MBzP) of 40 µg.L-1, or 30 µg.g-1 for creatinine.

The Agency reiterates that the substitution of carcinogenic, mutagenic and reprotoxic substances by less harmful substances or processes is a priority for chemical risk prevention in the workplace in France.