showed drowsiness starting in the early after noon and later becoming more severe Com plaints of loss of appetite and nausea at these relatively low exposures were less common See Hygienic Guide TEPP (tetraethyl pyrophosphate) is the active ingredient in an insecticide mixture that goes by the same name Since the esti mated fatal dose for a human being is ap proximately 600 mg taken orally, it is m the class of highly toxic materials In its use, toxic dust respirators or supplied air respirators and protective clothing which will completely prevent skin contact should be worn Anyone with a severe headache or a feeling of tightness or constriction in the chest should be removed immediately from the exposure 1.1.2.2- Tetrabromoethane (acetylene tetrabromide) is a high-boiling, heavy, yellow ish liquid used as an indicator liquid in gauges and for separating minerals by density Its low vapor pressure at room temperature makes it safer to handle than might be ex pected The LDjo for rabbits and guinea pigs is about 0 4 gm per kg of body weight Exposure to the vapor causes respiratory irritation and damage of the liver appearing a few days after a single acute exposure 1.1.2.2- Tetrachloroethane (acetylene tet rachloride) is an excellent solvent for a num ber of paints and lacquers It is also a very dangerous compound since inhalation of it at a concentration that is barely perceptible by odor can lead to extensive liver damage Tetrachloroethylene (perchloroethylene) is a chlorinated solvent used primarily for de greasing It is similar m its properties to trichloroethylene except that its boiling point is slightly above that of water so that boiling degreasers containing it automatically keep themselves dry without loss of solvent Its most important toxic effect is depression of the central nervous system In experi mental exposures of human subjects, those exposed to concentrations greater than 200 ppm promptly suffered central nervous sys tem symptoms, while those exposed to about 100 ppm did not See Hygienic Guide Tetraethyl lead--see Lead Also see Hygenic Guide 1375

trol panels involving high voltage (more than 550 volts) should be completely en closed Doors should have locks and con tacts wired in the control circuit to short circuit the capacitors when door or panel is opened A manually operated switch will serve as an additional safety measure, assunng complete discharge of the capaci tors 4 Back doors of machines and panels should be kept locked or interlocked to prevent tampering 5 A fused safety switch or circuit breaker should be located conveniently near the welding machine so that power supply circuits may be opened before a man services the machine and its controls 6 The point-of-operation hazard should be eliminated by suitable guards Enclosure guards, gate guards, two-hand controls, and similar standard guards as designed for punch press operations are applicable 7 A flash welding machine should have a shield or hood to control flash and fumes, and a ventilating system to carry off the metallic dust and oil fumes 8 Where flying sparks are not confined, the operators and nearby persons should be protected by shields of safety glass or other transparent material 9 Foot switches, air or electrical, should be guarded to prevent accidental opera tion Arc Welding and Cutting Arc welding is a process for joining metals by heating with an electric arc or arcs with or without the application of pressure and with or without the use of filler metal The process includes shielded welding which uses gas or a solid flux to blanket the weld Arc welding is used to fabricate nearly all types of carbon or alloy steels, the common nonferrous metals, and is indispensable in the repair and reclamation of metallic ma chine parts Arc cutting is used only for rough cuts or for scrapping because of the unevenness of the cut obtained It has been used for under water cutting in salvaging operations Oxy- arc or arc-oxygen cutting is used for finer cutting and is especially useful for cutting metals that do not oxidize readily For arc welding or cutting, two welding leads, the electrode lead and the work lead, are required from the source of current supply Usually, one lead is connected to the work and the other to the electrode holder The work lead (cable) is the most satisfactory means of providing the return (ground) circuit to the welding machine (Fig 31-6), but in some cases operating conditions may require the use of a grounded steel structure Power supply Either AC or DC may be used for arc weld ing or cutting of any kind, including carbon arc cutting and cutting with heavily coated electrodes With small diameter electrodes used on thin sheets for manual arc welding, current values vary from 10 to 50 amp For most manual welding, because the welder must withstand the heat, current values should not exceed 500 or 600 amp Automatic machine arc welding may use current values up to 200 amp or even higher on special applications Such operations employ AC only for more than 500 to 600 amp because with AC "arc blow" (swerving of the arc path caused by magnetic forces) is almost completely absent Arc blow is especially detrimental when higher current values are used Converters Commercial AC and DC power supplies are not suitable for arc welding Conse quently, to convert commercial power for arc welding, a rectifier must be used for DC welding, and a transformer for AC weld ing A motor generator may also be used to produce alternating or direct current Since these welding converters are sub ject to abuse and are given little expert atten tion as compared to ordinary electrical equip ment, they should be well protected, both mechanically and electrically Often the machines are moved about, so convenient primary power receptacles should be pro vided about the shop or construction opera tion Plugs and receptables should meet the requirements of Underwriters' Laboratories, Inc AC transformers for welding are usually 933

Lead prices now at 21C/lb. with some expectation that it may drop lower.

Do cases of lead poisoning occur in significant numbers in American Industry?

Sours very truly, r y U&f' -c-t' CiC N 5472 STHTL GASOLINE CORPGMTI0H GHRSLER BUILDING Bit O M , February II, 1931, To all Division Managers: Gentlemen: I believe that all Division Managers have had gone discussion on the question of lead in non-premium gasoline, fie have been authorised by the Surgeon General to license our Ethyl customers to use up to 1-1/2 ccs of lead in non premium gasoline with the understanding that we shall set a definite color for all such non-premium gasoline containing lead (such as all blue or all green) and that furthermore each pump shall be marked with the Ethyl warning plate.

The lead was reported in quantities per square inch.

Usage of Michigan Critical Materials as Reported to MATS* (Adjusted by the Plants in Their MDNR Reports) Material Lbs. of Usage Acrylic Acid Acrylonitrile Aniline Antimony Arsenic Benzene Cadmium Chromium Cloroprene Cobalt Copper Cyanides Dichlorobenzenes Formaldehyde Hydrazenc Hydroquinone Hypochlorite Lead Lithium Nickel Phenol Selenium Silver Silicon-Dioxide Coated Lead Chromate Styrene Tetracloroethylene Thiourea Triaryl Phosphate Esters Trichloroethylene Vinyl Chloride Zinc 251,707 641,133 90 830,571 11,157 385,028 3,311 81,377 24,676 210 321,704 923,069 2,542 488,965 130 1 15,841,758 626,027 123 126,624 5,839 127 25 2,317 1,413,986 1,095 18 160,022 91,849 118 1,085,724 Unreported to MATS Detroit Industrial Engine Research & Engineering Center Research - Glendale Troy - Tractor Principal Users PPV - Paint PPV - Paint MCC, Dbn.

Polich-ol Bransing Liquid Shoop r.nrking Liquid Hon-eorrodlble Graphite Oslo Leaded Dine Pigoenta Ferfeet Itothod Bed Lead Shingle stain 1906 Flat-Tone - First node in Paate Fora Old Dutch Enamel Handcraft Stains Golden Oak Stain Poroh & Lasn Furniture Enamel Galvanised Iron primer ' Dancing Floor VtaL : Graphite Pipe Joint & Gasket Coepound .

^-i >II r'f ^^VfcriUn - LEAD INDUSTRIES ASSOCIATION t CAST 4ttt STRICT MOV YORK 17, H.

usesul had.thi wonih rm<.ial: W\ shall sisting white-lead paint.

MC-11355 1 col. x 6 inches (or 84 lines) GLD32448 MOUND CITY'S LEAD-ZINC-TITANIUM HOUSE PAINT B*CCNfM...

It cannot be said that the diagnosis of lead encephalopathy has been established without question.

Polich-ol Bransing Liquid Shoop r.nrking Liquid Hon-eorrodlble Graphite Oslo Leaded Dine Pigoenta Ferfeet Itothod Bed Lead Shingle stain 1906 Flat-Tone - First node in Paate Fora Old Dutch Enamel Handcraft Stains Golden Oak Stain Poroh & Lasn Furniture Enamel Galvanised Iron primer ' Dancing Floor VtaL : Graphite Pipe Joint & Gasket Coepound .

To the Stockholders of National Lead Company'.

It turned out that there was 0.01$ of such lead In this sample.