Not an attorney, but as I understand the law, with the exception of a very few people that have "Privileged Communications", such as your attorney, a religious confessor, etc, anyone CAN file a complaint with OSHA regarding workplace safety, whether they are an employee of the business or not.
The main priority of OSHA inspections is to ensure the safety of the workers and customers to a business. OSHA: Occupational Safety and Health Administration
You report a health and safety issue by telling someone in authority about it. That could be a supervisor, manager, company officer, union representative, or OSHA or the equivalent in your location.
Typically, you report health and safety issues to a representative of your employer. This could be your foreman, supervisor, manager, the personnel office, or a designated "safety representative" or contact. If you are in the US, you can also file a health and safety complaint with your nearest OSHA office. Your employer is required by law to post basic OSHA information where it can be seen by all employees. There should be contact information there.
Since OSHA does not certify workers, the answer is nowhere.
40,000 investigating officers. (2012)
30 days
10
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Anyone can report to OSHA what they believe to be a violation of OSHA requirements, but only an employee can file a formal complaint with OSHA alleging that the employer has violated OSHA requirements. Complaints from non-employees are likely to receive less intense attention, unless they come from clearly knowledgeable healtha and safety professionals or relate to extremely hazardous situations.
Contact your local OSHA office to report this.
An OSHA inspection is a process in which a representative of the Occupational Safety and Health Administation comes to your place of business, inspects the workplace for compliance with the OSHA regulations, interviews employees privately, and reviews the records that the OSHA regulations require be kept by your company. The inspection may result in citations (requirements to fix problems) or fines. Certain rules and regulation in the workplace and operations of sites such as construction sites were created by OSHA to improve safety of the workers. If they have found companies operating without being compliant to their rules, they give them penalties to pay for - something that is better than having to pay for someone's life.
Report to them or Osha if they don't take it seriously.