I would not be too concerned about things like this, there are far more harmful carcinogenic materials around you....such as synthetic drugs, herbicides, pesticides, metal in your old fillings..etc (I could go on)
The harmful components used in the construction of the cases are in such small quantities that its almost a non concern!
Of course it has not rained in Johannesburg, South Africa yet... it's a few weeks overdue and my sinus might be at fault.
But I am slightly concerned.