When damage means ‘harm or injury’ it is an uncountable noun and so
▪ It
is never used in the plural
▪ It
never comes after a or a number
✗ These toxins can cause damages to the
lungs and brains.
✓ These toxins can cause damage to the
lungs and brains.
✗ They should consider the serious damages
that their decisions may cause.
✓ They should consider the serious damage
that their decisions may cause.