Gravano lays out how they dealt with them in his book. Sometimes the mob just got a straight-up payoff to keep the union from interfering with the the job. Other times they used the threat of union problems to force developers to use certain companies.

Trump used S&A concrete (owned secretly by Castellano and Salerno) to build some of his buildings. In an interview featured in the documentary "Trump Dynasty", he pretty much just brushed it off as the cost of doing business.