Officials say four people were hospitalized yesterday as a result of a toxic cloud that was released from Precision Castparts in Milwaukie, Oregon. Officials urged residents within a half-mile of the facility to close all doors and windows and remain inside. Two Clackamas County firefighters and two employees of the business were taken to a hospital for treatment of minor respiratory problems. Fire and rescue officials say a hydrofluoric nitric acid cloud leaked from the building shortly before 6 p.m. after titanium in a vat of acid created a chemical reaction following an electrical failure.