sentences:  A base camp (named "Camp Hunziker" after Richard Overton Hunziker, the USAF general in charge of the operation) was created at the crash site; it included a heliport, igloos, generators and communications facilities.A "zero line" delineating the by area in which alpha particle contamination could be measured was established by 25 January, four days after the crash.The line was subsequently used to control decontamination of personnel and vehicles.