After a public hearing at which any person may be heard, the director shall provide by regulation for the employment in any occupation of individuals whose earning capacity is impaired by physical or mental deficiency at wages lower than the wage rate applicable under sections 290.500 to 290.530. The individuals shall be employed as the director finds appropriate to prevent curtailment of opportunities for employment, to avoid undue hardship, and to safeguard the wage rate applicable under sections 290.500 to 290.530, except that no individual who maintains a production level within the limits required of other employees shall be paid less than the wage rate applicable under sections 290.500 to 290.530. Employees affected or their guardians shall be given reasonable notice of this hearing.