Welding Operations

Metal welding is a fabrication process whereby two or more parts are fused together by means of heat forming a joint as the parts cool. Multiple industrial and manufacturing facilities regularly use a variety of welding processes and materials. Welding operations can create emissions of highly toxic heavy metals including lead, hexavalent chromium, copper, nickel and cadmium. These toxic pollutants can cause adverse health effects, including cancer.

APCD Rule 11, which lists exemptions from permitting requirements, has an exemption for welding operations that do not create elevated health risks. Due to the potential health risks created by welding operations, the APCD established a process to evaluate welding operations in San Diego County.

Public Meeting

The District held a public meeting on April 20, 2022 to discuss potential health risks from welding operations, methodologies to calculate emissions and health risks, and existing permitting requirements.

Watch the meeting on YouTube.

Download the Presentation Slides

Welding Operations Map

The map below shows locations of facilities where welding operations are conducted. (Full Screen Map) (download map data)

Compliance Advisory, Methodologies, and Tools

MIG welding is used in the automotive industry for repairing vehicle exhausts and in creating homes and buildings. It is one of the most common types of welding. This is a type of arc welding that uses a continuous wire called an electrode. This operation utilizes a shielding gas that travels through the welding gun and protects against contamination.

TIG welding also uses electric arc like MIG.  TIG welding uses an electrode made of tungsten. Tungsten is one of the toughest metal materials and it will not dissolve or burn off. Welding can be done through a process known as fusion which might use a filler metal. TIG also uses an external gas supply, such as argon or helium. Aerospace and automotive operations also use TIG welding as well as other industrial operations.

Stick welding can be portable. Stick welding is used in construction, maintenance and repair, underwater pipelines, and industrial fabrication. For this type of welding a shielded metal arc welding (or more commonly known as stick welding) is used.  A consumable and protected electrode, or stick is also used. The stick softens and combines metals by heating with an arc between a covered metal electrode and the base metal workpiece. As the stick melts, its protective cover also melts and shields the weld area from oxygen and other gases that may be in the air.

Flux-cored arc welding is similar to MIG welding because both use continuous wire and power supplies. A continuous electrode is combined with a base metal. The electrode is a hollow tube filled with flux that is fed through the weld gun and into the weld pool. When welding outdoors, a flux shield offers protection against weather elements. This type of welding is used for welding thicker metals and is used in machining industries.