Oregon Administrative Rules › Chapter 333 - OREGON HEALTH AUTHORITY, PUBLIC HEALTH DIVISION › Division 16 - HAZARDOUS SUBSTANCES › Section 333-016-0020 - Testing Procedures for Hazardous Substances

Current through Register Vol. 63, No. 7, July 1, 2024
Method of testing toxic substances. The method of testing the
				toxic substances defined in OAR
				333-016-0005(5)(c) and
				(6)(c)  is as follows:
(1) Acute dermal toxicity (single exposure).
			 In the acute exposures the agent is held in contact with the skin by means of a
			 sleeve for periods varying up to 24 hours. The sleeve, made of rubber dam or
			 other impervious material, is so constructed that the ends are reinforced with
			 additional strips and should fit snugly around the trunk of the animal. The
			 ends of the sleeve are tucked, permitting the central portion to "balloon" and
			 furnish a reservoir for the dose. The reservoir must have sufficient capacity
			 to contain the dose without pressure. In the following table are given the
			 dimensions of sleeves and the approximate body surface exposed to the test
			 substance. The sleeves may vary in size to accommodate smaller or larger
			 subjects. In the testing of unctuous materials that adhere readily to the skin,
			 mesh wire screen may be employed instead of the sleeve. The screen is padded
			 and raised approximately two centimeters from the exposed skin. In the case of
			 dry powder preparations, the skin and substance are moistened with
			 physiological saline prior to exposure. The sleeve is then slipped over the
			 gauze which holds the dose applied to the skin. In the case of finely divided
			 powders, the measured dose is evenly distributed on cotton gauze, which is then
			 secured to the area of exposure. (See
Table 1
.)
(2) Preparation of test animals. The animals
			 are prepared by clipping the skin of the trunk free of hair. Approximately
			 one-half of the animals are further prepared by making epidermal abrasions
			 every 2 centimeters or 3 centimeters longitudinally over the area of exposure.
			 The abrasions are sufficiently deep to penetrate the stratum corneum (horny
			 layer of the epidermis), but not to disturb the derma -- That is, not to obtain
			 bleeding.
(3) Procedures for
			 testing. The sleeve is slipped onto the animal which is then placed in a
			 comfortable but immobilized position in a multiple animal holder. Selected
			 doses of liquids and solutions are introduced under the sleeve. If there is
			 slight leakage from the sleeve which may occur during the first few hours of
			 exposure, it is collected and reapplied. Dosage levels are adjusted in
			 subsequent exposures (if necessary) to enable a calculation of a dose that
			 would be fatal to 50 percent of the animals. This can be determined from
			 mortality ratios obtained at various doses employed. At the end of 24 hours the
			 sleeves or screens are removed, the volume of unabsorbed material, if any, is
			 measured, and the skin reactions are noted. The subjects are cleaned by
			 thorough wiping, observed for gross symptoms of poisoning, and then observed
			 for two weeks.
Tables referenced are available from the
				  agency.
Stat. Auth.: ORS 453.095
Stats. Implemented: ORS 453.005 &
				  453.055