law: 173. Certain matters not to be passed into municipal drains.
  (1) No person shall throw, empty, or turn into any municipal drain or into any drain communicating with a municipal drain
  (a) any matter likely to injure the drain or to interfere with the free flow of its contents, or to affect prejudicially the treatment and disposal of its contents; or
  (b) any chemical, refuse or waste steam, or any liquid of a temperature higher than forty-fivedegrees centigrade, being refuse or steam which, or a liquid which when so heated, is, either alone or in combination with the contents of the drain, dangerous, or the cause of a nuisance, or prejudicial to health; or
  (c) any dangerous petroleum.
  (2) In this section, the expression "dangerous petroleum" has the same meaning as in the Petroleum Act, 1934 (30 of 1934).