OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at http://www.osha.gov.

November 3, 1986

Mr. Urs Bachmann
Project Manager
Sulzer Brothers, Inc.
207 Heritage Park
Lake Wyllis, South Carolina 29710

Dear Mr. Bachmann:

This is in response to your October 8 letter concerning the results of measurements taken in weaving rooms. In your letter you specifically requested information on the sufficiency of the number of samples taken, adequacy of the duration of measurements, and compliance with the Occupational Safety and Health Administration's (OSHA) permissible exposure limits (PEL) for cotton dust in a weaving operation.

The number of samples required depends on how many workers are in the area, and how many machines are tended by each worker. The number of samples per machine as shown in your sampling results appears to be sufficient. However, unless a worker spends about an equal amount of time on both machines, as in the case of tower 310, the exposure levels should not be averaged. Instead, it should be calculated based on the level and duration of exposure in each area. The same reasoning applies to tower 309 and 306.

The PEL for slashing and weaving operations is 750 ug/m3 mean concentration of lint-free respirable cotton dust as measured by a vertical elutriator or an equivalent instrument.

29 CFR 1910.1043 is the OSHA standard for occupational exposure to cotton dust. It applies to the control of employees exposure to cotton dust in all workplaces where employees are engaged in yarn manufacturing, slashing and weaving operations, or work in waste houses for textile operations. I am enclosing a copy of the cotton dust standard for your reference.


Edward J Baier
Directorate of Technical Support