The practice of "Professional Engineering" in the United States is governed by licensing statutes in all fifty states and the District of Columbia. Liability for incompetency is only indirectly affected by these statutes. The statutes do have an effect on the contractual relationships of the engineer and most states make a violation of the licensing sections a misdemeanor, punishable by fine and/or imprisonment.
Emil F. Sos Jr.,
Liability of Engineer for Defective Design,
19 Clev. St. L. Rev.
available at http://engagedscholarship.csuohio.edu/clevstlrev/vol19/iss1/22