Brazil nuts are only dangerous if you consume or eat too many of the Brazil nuts.
When you eat Brazil nuts in moderation they are healthy and nutritious for you.
But when you eat too many Brazil nuts then they become toxic to humans and can make the human sick or even be deadly.
But for the Brazil nuts to become toxic to humans so that it gets to the point of killing you the person needs to eat at least 50 or more Brazil nuts.
As long as you keep your consumption of Brazil nuts under 50 Brazil nuts per day you should be safe.
You'll likely get stomach cramps from eating the Brazil nuts before you actually ate enough of the Brazil nuts for them to be toxic or dangerous.