This publication includes the recommended procedures for sampling and methods of analysis for gases that may be formed during the use of various welding and allied processes. These gases include the following: (1) Ozone (O3) (2) Carbon Monoxide (CO) (3) Nitric Oxide (NO) + Nitrogen Dioxide (NO2) = Oxides of Nitrogen (NOx) (4) Gaseous Fluorides Summaries of the acceptable methods are presented in the body of this document. Detailed descriptions of NIOSH1 and OSHA2 methods and references are presented in the Annexes. This standard makes use of the International System of Units (SI).