If you are working for a business that is an "employer" and you are actually an "employee" of that business, I do not see any reason why the OSHA safety provisions would not apply to your employment at a main service. Generally, the duty for an employer to provide an employee with a safe workplace applies to all employers in the private sector regardless of the number of employees. Certain employers are exempt altogether, but those are few and far between.
There is a "general duty" provision under the OSHA regulations that require an employer to provide an employee with a workplace that is free from health hazards etc. There is a wealth of information online, although it can be overwhelming. There are also OSHA provisions that require an employer to provide an employee certain personal protective equipment (such as masks) in order to protect an employee from illness.
Quite honestly, I do not know how the agency would approach a situation wherein a maid service was requiring employees to work in people's homes and in potentially hazardous conditions. However, if you truly feel that you are working in an unhealthy and unsafe environment, I would first bring it to the attention of the employer and work with the employer in order to find some common ground and perhaps a good faith effort to resolve the issue.
OSHA does have a complaint procedure if you cannot resolve the issue. If you report your employer to OSHA, the law does have an anti-retaliation procedure, but I will tell you from my experience that it has very little protection. Only the OSHA agency itself can bring a claim against the employer and you not have a private action wherein you can hire your own personal attorney. Therefore, I would proceed with caution, almost assuming that if you get discharged it will be tough to have any legal recourse.
This may be one of those situations where you simply need to move on to a safer environment for your own health reasons.