Wood-protecting agents are compounds acting toxically on fungi and insects. If handled improperly or carelessly, they may exert an action harmful to health and safety of men. This action is concerning: a) workers employed at the production of wood-protecting agents; b) workers employed at the impregnation, or at the transport and handling of impregnated wood; c) inhabitants of buildings with impregnated wooden elements, or which have been treated against fungi. At the suggestion of the Scientific and Technical Committee for Wood Protection, medical institutes started investigations concerning the influence of wood-protecting agents on human health. A draft has been worked out on the terms of admissibility for the use of these agents. The toxicological specification of a wood-preserving agent has to include the results of the following tests: 1) Determination of hypertoxicity LD50 per os for rats; 2) Determination of toxicity LD50 per coeliacus for rats; 3) Determination of irritant action on the eye mucosa and the skin of the rabbit; 4) Determination of allergenic action on the skin of the guinea pig; 5) Determination of injuring action by histopathological method; 6) Determination of toxicity LD50 by inhalation after 4 hours by rats, given the content of the active substance in mg in 1 litre of air; 7) Determination of the quantity of wood-protecting agents in the air, by means of the cabin method, and their disappearance. The above mentioned determinations are to be carried out according to methods generally accepted for toxicological tests. In certain cases, they have to be adapted to the requirements of the wood-protecting agents tests. As a fundamental criterior for the evaluation of wood-protecting agents in relation to toxical noxiousness we take the toxicity per os of the whole compound, expressed in mg per kg of weight of the living experimental animal (LD50). The other determinations are of complementary character, and in the case of unfavourable results, they cause the agent to be classified at a lower class than having been classified by the fundamental criterion LD50 alone. A classification of 5 degrees has been worked out for the wood-protecting agents, based on the classification of Hodge-Sterner: Degree I: hypertoxic agent (LD50: below 50 mg/kg); Degree II: toxic agent (LD50: 51-150 mg/kg); Degree III: noxious agent (LD50: 151-500 mg/kg); Degree IV: less noxious agent (LD50: 501-5000 mg/kg); Degree V: practical not noxious agent (LD50: above 5000 mg/kg). In accordance with the accepted criteria the toxicity of some wood-protecting agents is as follows: 1) Arsenic compounds - Degree I of toxicity; 2) Sodium fluoride - Degree II of toxicity; 3) Sodium fluoride + chromium salts - Degree II of toxicity; 4) Fluoride/borates + chromium salts - Degree II of toxicity; 5) Zinc fluosilicate - Degree III of toxicity; 6) Bifluorides - Degree III of toxicity; 7) Borax, boric acid - Degree V of toxicity. In Poland the use of wood-protecting agents of the Degree I of toxicity is prohibited. It is planned to withdraw from use progressively wood-protecting agents having higher degrees of toxicity. The present draft and the suggested classification are of preliminary character. They are being submitted for further investigation and discussion to the authorities concerned with health protection and environmental protection.

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