What are the negative effects (cons) of a free trade agreement?

There is always a risk in trading and production. If a nation cannot compete because it truly needs to protect a vital business, then that becomes an unintended negative affect. And or if companies move from one country to another to produce cheaper products then the old nation loses jobs and the product once made in the old country must be purchased from the newer one at a lower price however, that may not help unemployed workers at all.