I see warnings of the erucic acid contained in mustard oil, e.g.
15 amazing facts and uses of mustard oil (Times of India):
According to celebrity nutritionist Sandhya Gugnani, "There was a myth attached to mustard oil...unfortunately it was considered unfit for consumption by countries like USA, Canada and Europe as it contained erucic acid which had an adverse effect on rats. But now it has been proved that it has no adverse impact on humans.
Mustard oil is considered one of the healthiest oils as compared to other oils as it has optimum ratio of omega 3 and omega 6 fatty acids and is low in saturated fats and high in MUFA (mono unsaturated fatty acids)."
'Mustard oil has health risks' (Times of India):
Mustard oil is banned for edible consumption in the EU, USA and Canada, principally due to its erucic acid content. The USFDA requires all mustard oil to be labelled "For External Use Only". Erucic acid is known to cause the following health risks: Accumulation of triglycerides in the heart; development of fibriotic lesions of the heart; increase in risk of lung cancer; and anaemia.
However, this oil contains moderate amounts of erucic acid. Consuming erucic acid rich oils like mustard oil can unleash a host of health problems which includes anemia, fibrocystic heart lesions and even lung cancer.