Sampling lead welding fumes inside helmets

March 22, 1995

MEMORANDUM FOR: R. DAVIS LAYNE
REGIONAL ADMINISTRATOR
REGION IV

FROM: JOHN B. MILES, JR., DIRECTOR
DIRECTORATE OF COMPLIANCE PROGRAMS

SUBJECT: Sampling for Lead Welding Fumes

This is in response to your letter dated November 14, requesting a change in OSHA sampling policy for welding operations. While we can agree with much of your rationale, studies have shown that overall worker exposure to metal fume generated during welding is lower when measured inside the helmet compared to outside. The following references support this conclusion and are the basis for the OSHA sampling protocol requirements.

Johnson, W.S.: An investigation into the True Exposures of Arc Welders by Means of Simultaneous Sampling Procedures. American Industrial Hygiene Association Journal 20:194-196 (1959).
Alpaugh, E.L.; Phillippo, K.A.; Pulisifer, H.C.:
Ventilation Requirements for Gas-Metal-Arc Welding. American Industrial Hygiene Association Journal 29:551-557 (1968).
Van Sandt, W.; Sharenbroch, I.: Modified Welder's Helmet using Spillproof Impingers. American Industrial Hygiene Association Journal 33:435-437 (1972).
Goller, J.W.; Paik, N.W.: A Comparison of Iron Oxide Fume Inside and Outside of Welding Helmet's. American Industrial Hygiene Association Journal 46:89-93 (1985).

In addition, the most recent review commission decision (attachment) essentially mandates this requirement. OSHA therefore, will still require that personal sampling for welding fume be conducted with the filter placed inside the welding helmet.

The requirement for sampling outside a respirator when monitoring for lead in construction is primarily to evaluate the level of respiratory protection afforded the employee and the extent of the airborne exposure. As you indicated in your letter, the problem with sampling inside a welding helmet is that one could be precluded from applying the full lead standard if the exposure is below the permissible exposure limit (PEL). A sample taken under a welding helmet that was below the PEL would negate the personal hygiene requirements of the lead standard. To provide adequate worker protection from this scenario, one would need to conduct sampling both inside and outside the welding helmet. Sampling under the welding helmet would determine the need for medical monitoring, engineering controls, and respiratory protection. If the documented exposure inside the helmet was below the PEL and the sample outside was above it, the outside sample can be used to evaluate the hygiene requirements.

While this letter does not change the OSHA sampling policy for welding operations it does provide a solution for not adequately protecting workers. If you have any questions or wish to discuss this more please contact [the Office of Health Enforcement at (202) 693-2190].

[Review Commission decision and OSHA regional memorandum reproduced on OSHA page; omitted here.]

[Corrected 12/6/2024]