Divorced Catholics are not excommunicated.
The American Church did place excommunication upon divorced people during the U.S. Bishops' Council of Baltimore in 1843. Believing this penalty was too severe, the Bishops withdrew the censure in 1884, though the penalty of excommunication for any Catholic who divorced and remarried outside the Church still remained. In 1977, Pope Paul VI, at the request of the American bishops, rescinded the directive of excommunication that had been in effect. Subsequently, Pope John Paul II called upon all pastors and the laity to help the divorced to not consider themselves as separated from the Church.
Though the penalty of excommunication has long been lifted, the rumor of excommunication has not gone away. Many divorced Catholics still think that they are excommunicated. That this is not true needs to be reinforced from the pulpit. Further, though a Catholic who divorces and remarries without an annulment is considered to be in an irregular marriage and is not open to receive the Eucharist, he or she is not excommunicated.