Upon request, the manufacturer of a hazardous substance or the producer of a mixture who has produced a mixture MSDS pursuant to the provisions of subdivision (b) of Section 6397 shall make available to any employer, whose employees may be exposed to its product in the workplace, an MSDS on its product. If the employer does not already have an MSDS and has not already made written inquiry within 12 months as to whether a substance or product is subject to the requirements of this chapter or if the employer has not already made written inquiry within 6 months as to whether any new, revised, or later information has been issued for a hazardous substance, the employer shall do so within seven working days of a request to do so by an employee or employee’s collective bargaining representative or physician. The employer may adopt reasonable procedures for acting upon such employee requests to avoid interruption of normal work operations. The manufacturer or the producer of a mixture MSDS pursuant to the provisions of Section 6397 shall answer such inquiries within 15 working days of their receipt, stating that the substance or product is subject to the requirements of this chapter and furnishing the most current MSDS or a statement that the MSDS is under development and the estimated completion date, or stating that it is not subject to the requirements of this chapter, with a brief explanation of why the chapter is not applicable. If an employer has not received a response from a manufacturer within 25 working days of the date the request was made, the employer shall send a copy of the request made of the manufacturer to the director with the notation that no response has been received.