Document 6bzRmENEbN6yrb2krKLw8JGg3

38--Industrial Toxicology DDT can be absorbed by ingestion, inhala tion, or application of an oil solution directly to the skin Rabbits have been acutely poisoned by a 5 percent od solution of DDT applied to the skin In the practical application of DDT as an insecticide, experience has been good Re ported cases of human poisoning have resulted from accidents rather than from proper appli cation of the material Contacts with the od solution should be avoided, and with power sprayers it is advisable to use an approved respirator if considerable spray kicks back into the operator's breathing zone Decaborane--see Boron hydrides. Derris is a powdered plant root, which con tains rotenone as its mam active ingredient See Rotenone. Diacetone alcohol is a flammable solvent Exposure of laboratory animals to the satu rated vapor, 2100 ppm, resulted in irritation of the eyes, running of the nose, excitement, and then sleepiness m about 20 minutes There are no cases of human poisoning on record This solvent is liable to be a fire hazard be cause the commercial material often contains acetone as an impurity in concentration great enough to substantially lower the flash point Diatomaceous earth is a form of sdica in the amorphous state Although it apparently is not as active in producing silicosis as its high content of free silica would lead one to expect, there have been a number of reports of silicosis from handling the material where the dust concentrations were high (see Chap ter 37, "Industrial Hygiene") If the temperature is raised to about 1000 F (538 C) m a calcining operation, the mate rial readily changes to enstobalite, which is a vigorous producer of silicosis It should be handled with the same precautions against dust used with other forms of free silica Diborane--see Boron hydrides 1,2-Dibromoethane (ethylene dibromide) is used mainly as a constituent of fumigation mixtures and of "leaded" gasoline To a 1140 limited extent, it has also been used as a fire extinguishing agent and solvent As an indus trial hazard, it is toxic by ingestion, by skin contact, and by inhalation On experimental animals it produces local irritation of the eyes and skm if applied di rectly, but produces severe bums and is ab sorbed through the skm if it is confined m con tact On ingestion and inhalation, it injures the lungs, liver, and kidneys and depresses the central nervous system Dichlorobenzene occurs as the three iso mers ortho, meta, and para All are flam mable liquids with low vapor pressures, but they are sufficiently volatile to produce toxic symptoms if handled m the open in a con fined area They are used primarily as in secticides, as intermediates in the dye industry, and to some extent as solvents Development of cataract and of liver symptoms from chronic exposure to these compounds in industry has been reported Dichlorodifluoromethane (Refrigerant 12) is about as physiologically inert a substance as one could find It has no real toxic effects until the concentration becomes high enough to reduce the oxygen content of the atmos phere Since it is a refrigerant gas normally under fairly high pressure, it will freeze tis sue upon which it is directed It may also de compose if brought into contact with an open flame or a red-hot surface and produce irri tating and toxic decomposition products 1.1- Dichloroethane (ethyhdene chloride) was formerly used as an inhalation anesthetic but has been completely displaced by safer materials It is still used to some extent as a solvent m industry Its acute effect is that of an anesthetic and narcotic, and chronically it characteristically produces symptoms and signs of digestive and central nervous system irri tations 1.2- Dichloroethane (ethylene dichloride) is a commonly used, low-boiling solvent Quali tatively, its effects are very similar to those of 1,1-dichloroethane 1.2- Dichloroethylene (acetylene dichlonde) is a widely used solvent of low fire hazard and