Welding fume and iron oxide exposure limits

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

July 8, 1991

MEMORANDUM FOR: LINDA R. ANKU
REGIONAL ADMINISTRATOR

FROM: PATRICIA K. CLARK, DIRECTOR
DIRECTORATE OF COMPLIANCE PROGRAMS

SUBJECT: Enforcement of the Welding Fume PEL

This is in response to your memorandum of May 31, in which you requested clarification regarding the applicability of the welding fume PEL versus the iron oxide PEL.

The discussion concerning the welding fume PEL in 29 CFR 1910.1000 states that the limit of 5mg/m³ "applies to the total fume concentration generated during the welding of iron, mild steel, or aluminum". OSHA believed that a PEL for mixtures such as welding fume was needed to address the complex problem of synergistic exposures and their health effects. Welding fume may consist of a large number of metallic oxides and other toxic gases including, in the case of the welding of iron metals, manganese, silicate, and various organic binders.

Therefore, the welding fume PEL shall be applied in those welding operations involving the welding of iron, mild steel, or aluminum unless a more protective substance specific standard may be applied (eg. exposure to lead or copper contaminants). The iron oxide PEL shall be applied to those operations other than welding which generate exposures to iron oxide fume.

Please contact my office if you need further clarification on this issue.
May 31, 1991

MEMORANDUM FOR: PATRICIA K. CLARK, DIRECTOR DIRECTORATE OF COMPLIANCE PROGRAMS

FROM: LINDA R. ANKU
REGIONAL ADMINISTRATOR

SUBJECT: WELDING FUME PEL

As you are aware, the PELs were updated in a Federal Register notice dated January 19, 1989. At that time a new PEL of 5 mg/m³ was established for welding fume. In addition, OSHA has a PEL for the iron oxide fume which, at 10 mg/m³, is higher than the welding fume PEL. Many welding operations involve the generation of iron oxide fume which could create confusion as to which PEL to apply, the higher iron oxide PEL or the lower welding fume PEL. It is proposed that the welding fume PEL be applied to all welding operations including those with exposure to iron oxide fume, and that the iron oxide fume PEL be applied to those operations other than welding which generate exposures to iron oxide fume.

Your comments on this issue are requested. Please contact Jim Johnston of my staff (FTS 596-1201) if there are any questions.