Maryland Code, Labor and Employment § 4-401

(a) Each employer who, under a collective bargaining agreement, deducts dues from an employee's pay for payment to a union shall make the payment within 30 days after it is required.

(b) Each employer or union official who, under a collective bargaining or other agreement with an employee, agrees to make a payment into a health or welfare fund, a pension fund, a vacation plan, or any other similar fund or plan for employees shall make the payment within 30 days after it is required.