After Dennis Nedry turned the electricity off he told John Hammond that he couldn't get Jurassic Park back online without Dennis. He made frequent announcements over the loudspeaker informing the other employees of the position of the approaching storm. In the first edition of the script, Hammond was greatly concerned for Arnold's health due to his constant smoking. Arnold was usually shown smoking a cigarette.
His catchphrase was 'Hold on to your butts,' which he repeated twice in the film.
Ray Arnold, full name possibly John Raymond Allen Arnold, is the chief engineer of Jurassic Park.