Which method cannot be used for OSHA compliance according to the rules?

The correct method that cannot be used for OSHA compliance according to the rules is transmission electron microscopy. While this technique is a powerful analytical tool that can provide detailed information about particle size, composition, and morphology, it is not directly aligned with the methods sanctioned by OSHA for compliance purposes.

OSHA typically specifies methods that are practical and accessible for employers and employees in industrial hygiene settings. These methods are often selected for their reliability, ease of use, and the ability to provide compliance with permissible exposure limits (PELs). The other methods mentioned, such as phase contrast microscopy, amperometric cells, and alpha radiation analysis, have established protocols within OSHA guidelines and are recognized for their effectiveness in evaluating worker exposure to hazardous substances.

Phase contrast microscopy, for instance, is frequently utilized for airborne asbestos fiber analysis, while amperometric methods can be employed for monitoring specific gas concentrations. Alpha radiation analysis can be used to measure radioactive materials present in workplace settings. These methods align with OSHA's goals to establish safe working environments and provide substantial evidence to ensure compliance with health and safety regulations.

In summary, transmission electron microscopy, while technically robust, is not categorized under the OSHA-compliant methods due to operational practicality and the nature of its application in occupational settings.