Document LBmB0ra7Bn1eMweYBwjmzJ5z

Elements of Industrial Toxicology Industrial toxicology is primarily concerned with the physiological effects produced m individuals who have been exposed to harm ful materials during the course of their em ployment The constant introduction of new industrial processes, operations, and tech niques involving new chemicals n ake a knowledge of toxicology important to the safety professional who is frequently called upon for advice concerning the dangers as sociated with the use of various chemical agents A safety professional setting up a program to minimize injury from the use of mechanical tools will be concerned with the physical characteristics of the machine tool or ma chinery and the manner m which the vanous parts of the machine come into contact with the operator and cause harm Similarly, he is concerned with, how chemical agents can approach or contact individuals, how that contact can be prevented, and how extensive the injury can be if contact does occut, based on the properties of the chemical agents in volved The principle job of the industrial toxicolo gist is to obtain sufficient basic information concerning the biological action and potential toxicity of a chemical substance so that its relative hazard to man may be ascertained The toxicologist must analyze the points of attack of chemical agents and clarify the mechanism of effect, with the view towards prevention, recognition, and treatment of chemical intoxications Hamilton and Hardy (see "References") state that industrial and nonindustnal toxi cology differ in three important ways First is the manner m which the material is absorbed into the body In nonindustnal cases, the most common way is orally, through the mouth, then through inhalation, and lastly through skin absorption, in industrial cases, entrance through the respiratory tract with the inspired air is of overwhelming impor tance compared with skin absorption or en trance through the gastro-intestmaJ tract The second difference is that industrial poisoning tends to be of the chronic variety, whereas nonindustnal poisoning is more often acute But acute cases do occur in in dustry, although they are far less numerous than the chronic cases The third difference is that generally mdustnal poisoning is a result of exposure to a mixture of substances compared with a single matenal for nonindustnal cases These harm ful mdustnal matenals are absorbed without the voluntary participation of the persons concerned, often hardly observed or even completely unobserved Chemical Toxicity If administered in a suitable manner and in sufficient dosage, practically any substance can be harmful to man It is recognized, therefore, that there are degrees of harmfulness and degrees of safeness for all matenals These degrees are pnmanly related to the amount of matenal that is present in the body--a relationship exists between the biologic effect of a chemical agent and its dose or concentration m the human body Many chemical agents are nonselective in their action on tissues or cells, they may exert a harmful effect on all living matter Other chemical agents may act only on speci fic cells Another agent may be harmful only to certain species, other species may have built-in protective devices Toxicity is relative It refers to a harmful effect on some biologic mechanism The term "toxicity" is commonly used in compar ing one chemical agent with another, but such comparison is meaningless if the biologic mechanism and the conditions under which the harmful effects occur are not specified Pnnci (see "References") states that a chemical stimulus may be considered to have produced a toxic effect when it satisfies the following criteria 1 An observable or measurable physiologic deviation has been produced m any organ or organ system The change may be anatomic in character and may be accelera tion or inhibition of a normal physiolog ical process, or it may consist of a specific biochemical change This chapter was revised by Julian B Olishifski, P E , based upon reviews by selected members of the National Safety Council 1300