490.733.  Hazardous materials, defined, admission of samples into evidence, when — photos, videotapes or lab reports deemed competent evidence. — 1.  As used in this section, the term "hazardous materials" means any substance which is capable of posing an unreasonable risk to health, safety and property.  It shall include any controlled substance or controlled substance analogue as defined in section 195.010 or any substance which by its nature is explosive, flammable, corrosive, poisonous, radioactive, a biological hazard or a material which may cause spontaneous combustion.  It shall include, but not be limited to, substances listed in the Table of Hazardous Materials contained in the Code of Federal Regulations-Title 49 and the National Fire Protection Association's Fire Protection Guide on Hazardous Materials.

  2.  Notwithstanding the provisions of section 575.100 and with the approval of the affected court, any law enforcement officer who seizes hazardous materials as evidence related to a criminal investigation may collect representative samples of such hazardous materials, and destroy or dispose of, or direct another person to destroy or dispose of the remaining quantity of such hazardous materials.

  3.  In any prosecution, representative samples of hazardous materials accompanied by photographs, videotapes, laboratory analysis reports or other means used to verify and document the identity and quantity of the material shall be deemed competent evidence of such hazardous materials and shall be admissible in any proceeding, hearing or trial as if such materials had been introduced as evidence.

  4.  In any prosecution for violation of chapter 195 in which the weight or quantity of a controlled substance is an element of the offense, the weight or quantity of the controlled substance necessary to prove the element of the offense shall be held as evidence; except that, any amount of controlled substance in excess of that which is necessary to prove the offense may be destroyed at the direction of the seizing law enforcement officer.  Photographs, videotapes and laboratory analysis reports shall be admissible in any proceeding, hearing or trial as if such excess amount of controlled substances had been introduced as evidence.