the core-making workshops had the highest concentration for at least two nitrosamines , n-nitrosodimethylamine ( ndma ) and n-nitrosoethylmethylamine ( nema ) , but the levels of ndma never exceeded 0.35 microgram/m3 with an arithmetic mean between 0.23 and 0.02 microgram/m3 .
C0028197
nitrosamines
C0012431
ndma