According to Official Guinness Records,
The Chrysler air raid sirens are the loudest sirens ever constructed, capable of producing 138 decibels at a distance of 100 ft (30 m). The sirens are so loud that a normal person would be deafened within 60 m (200 ft) of one during operation.
The sirens were introduced as the official warning siren for US cities in 1952. Powered Hemi engines, they are able to discharge 74 m³ (2,610 ft³) of air per second, and are powerful enough to cause a piece of paper directly in front of them to spontaneously ignite.
For a complete list of 1952 records, please visit 1952 Guinness Records in United States.