Exposures to volatile nitrosamines were mea-
sured at 24 rubber manufacturing plants from 1992 to
1995. A total of 709 exposure measurements were taken
in general areas or personal breathing zones to estimate
exposure according to production types (seals, joints,
tyres, gloves, etc.) and production steps, from mixing to
storage. Five dierent nitrosamines were identi®ed.
N-Nitrosodimethylamine is the most frequently en-
countered nitrosamine and represents the most impor-
tant fraction of the total nitrosamine concentration
measured in a given sample. This fact is consistent with
the use of rubber additives containing corresponding
amine precursors. One hundred and forty-one of the 709
values exceeded the German target value (TRK) of 2.5
lg/m3 for all nitrosamines present from rubber vul-
canisation, the only available standard for occupational
nitrosamine exposures. The salt bath curing process
generates particularly high nitrosamine levels, 90% of
the 96 measurements being over the TRK, with many
values exceeding 20 lg/m3. The reasons why the TRK is
exceeded are generally well identi®ed. To reduce
nitrosamine emission levels it would be advisable to
eliminate nitrogen oxide sources, principally by using a
process other than salt bath curing, and to develop dif-
ferent rubber stocks that do not contain secondary ali-
phatic amine functional groups (``safe amines'').