Maryland Labor and Employment Section 5-402
§ 5-402.
  Sections 5-404 through 5-409 of this subtitle do not apply to:
    (1)   a railroad that is subject to the Federal Railroad Safety Act of 1970 and the jurisdiction of the Federal Railroad Administration;
    (2)   a landfill in the State;
    (3)   a person who:
      (i)   is engaged in the business of providing commercial or residential garbage and refuse pickup and disposal service while actually engaging in the pickup and disposal of garbage and refuse; and
      (ii)   does not pick up, transport, treat, store, or dispose of controlled hazardous substances that are regulated under Title 7, Subtitle 2 of the Environment Article; or
    (4)   an analytical, educational, or research and development laboratory.