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Subpart Z 29 CFR 1910 IH Toxicology IH Toxicology.

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Presentation on theme: "Subpart Z 29 CFR 1910 IH Toxicology IH Toxicology."— Presentation transcript:

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2 Subpart Z 29 CFR 1910 IH Toxicology IH Toxicology

3 Industrial Hygiene Anticipation Recognition Evaluation Control –of environmental factors that can cause sickness or disease

4 Hygienist Activities On which function does an IH* spend the most time? *industrial hygienist Evaluation Which most Difficult? Anticipation Which should spend most time? Control

5 Control Methods

6 Control at the Source Chemical substitution Redesign the process Isolate the process Enclose the process Mechanize

7 Control of the Path Local exhaust ventilation General ventilation Housekeeping Work methods (wetting down, etc.)

8 Control at the Worker Respirators and other PPE Administrative controls Enclose the worker Hygiene facilities and practices

9 Hierarchy of Control Control the source Control the path Control the exposure at the worker

10 Hierarchy of Control Engineering Administration Personal protective equipment (PPE)

11 Types of Illnesses - Time Acute - a disease that develops quickly after exposure Chronic - a disease that develops long after exposure Latency Period - the time between the first exposure and the development of disease

12 Routes of Exposure Breathe the chemical – inhalation Swallow the chemical – ingestion Absorb through skin - skin absorption In all cases, chemicals can travel through the body.

13 Important Body Organs LungsKidney Blood FormingReproductive Nervous System Liver –brain –nerves

14 Forms of Chemicals Particles –Dust - formed by Grinding /breaking - large particles –Smoke - formed by burning - large particles –Fume - formed by heating - small particles

15 Forms of Chemicals Gasses –Gas - at room temperature –Vapor - heat to turn to gas --- –Droplets - agitating a liquid

16 What is Dose? Concentration & Time

17 Chemical Interaction Additive Effects2 + 2 = 4 Synergistic Effects2 + 3 = 9 Potentiation Effects2 + 0 = 8 Antagonistic Effects4 + 6 = 5

18 Signs of Exposure Dust, Mist, Smoke in the air Accumulation of dust or oils Unusual Smells Unusual Tastes Burning in the eyes Nose throat irritation Feel better during vacation

19 Contributory Factors to Toxicity Dose Absorption Rate of Transformation Excretion Rate Human Factors Route of Entry

20 Measuring Particles Concentration Weight of substance in volume of air Weight in milligrams - mg Volume in cubic meters m 3 mg/m 3 = milligrams per cubic meter

21 Measuring Gasses or Vapors Volume concentration of gas in air Parts per million –Parts of gas in million parts of air –Cups in a million cups –Quarts in a million quarts –Similar to per cent, which is actually parts per hundred

22 OSHA PEL’s PEL = Permissible Exposure Limit The concentration of a chemical a worker can be exposed to... –8 hours per day –working lifetime without experiencing health problems

23 Kinds of PEL’s TWA = Time Weighted Average Levels vary over a day OK for chemicals causing chronic disease

24 TWA Example #1

25 TWA Example #2

26 Ceiling

27 Ceiling PEL Concentrations can never exceed Indicated by OSHA as “C” Appropriate for chemicals causing acute disease If can’t measure instantaneously, take 15 minute (worst case) sample

28 STEL

29 STEL STEL = Short term exposure limit Period of time shown in standard where PEL can be exceeded Still an absolute maximum that can not be exceeded (a ceiling) Must still meet the TWA

30 Skin Notation If OSHA says “skin,” then can’t have any skin contact Appropriate where there is [a possibility of] skin absorption

31 How Do We Get These PEL’s? Concensus standards ACGIH, 1968 ANSI New standards attempted to upgrade not successful

32 Other Sources of Standards ACGIH - TLV’s NIOSH - REL’s Company standards

33 Table Z-1 Based on 1968 ACGIH Lists chemical name CAS (identifying) number PEL (Time Weighted Average) Skin (if applies) Ceiling (if applies)

34 As stated in a previous memorandum dated November 8, 1996: Compliance officers can choose one of two approaches for employees who work extended work shifts beyond 8-hours. The choice taken will depend on the nature of the hazardous chemical. 11/10/ OSHA policy regarding PEL adjustments for extend work shifts

35 The first approach is to sample what the compliance officer believes to be the worst continuous 8-hour work period of the entire extended work shift. PEL Adjustments

36 The second approach is to collect multiple samples over the entire work shift. Sampling is done such that multiple personal samples are collected during the first 8-hour work period and additional samples are collected for the extended work shift. Unless a compliance officer is dealing with lead, the PEL in this approach is calculated based upon the worst 8- hours of exposure during the entire work shift.

37 Table Z-2 Based on ANSI standards Lists chemical name CAS number TWA Acceptable ceiling Peak Duration

38 "Acceptable ceiling concentrations." An employee's exposure to a substance listed in Table Z-2 shall not exceed at any time during an 8-hour shift the ceiling concentration limit given for the substance except for: –A time period, and up to a concentration not exceeding the maximum duration and concentration allowed in the column under "acceptable maximum peak above the acceptable ceiling concentration for an 8-hour shift" (b) - Table Z-2

39 The substances listed can have limits expressed as: –8-hour TWAs –Ceilings –Peaks If a substance has both ceiling and peak limits, the peak is the level never to be exceeded Employee exposure level exceeding the ceiling but under the peak are required to comply with the margin notes provided in the table Peak (b) - Table Z-2

40 Example: –During 8-hour work shift, an employee may be exposed to Substance A (with a 10 ppm TWA, 25 ppm ceiling, and 50 ppm peak) above 25 ppm (but never above 50 ppm) only for a maximum period of 10 minutes. –Such exposure must be compensated by exposures to concentrations less than 10 ppm so that the cumulative exposure for the entire 8-hour work shift does not exceed a weighted average of 10 ppm (b) - Table Z-2

41 Table Z-3 Mineral Dusts –silica and silicates –graphite –coal dust –Inert or nuisance dusts (particulates not otherwise classified) Respirable: < 10 microns –separated with cyclone

42 Substance Specific Standards 31 specific chemicals –asbestos –benzene –coal tar pitch volatiles –lead –formaldehyde –arsenic

43 Substance Specific Requirements Air monitoring Control of exposure Work practices Respiratory protection Medical surveillance –medical removal (lead) Record keeping Worker training

44 Air Monitoring: Who, What, Where? Worst case sampling Representative sampling Personal vs. area sampling What conditions can affect sampling results?

45 Chemical Properties Flashpoint Vapor Density Vapor Pressure Specific Gravity Evaporation Rate

46 Air Monitoring Pump Tube Collection device Direct reading

47 Air Monitoring Calibrate pump with collection device before and after each sample Sample minimum of one hour less than full shift (for OSHA compliance)

48 Napthalene Exposures 15 ppm for 6 hours 5 ppm for 2 hours

49 Compute TWA 15 ppm x 6 hours = 90 ppm hrs 5 ppm x 2 hour = 10 ppm hrs 8 hours 100 ppm hrs ____________________________ 100 ppm hrs ÷ 8 hours = 13.8 ppm

50 Less Than Full Shift Sample? 15 ppmx 7 hours =105 ppm hrs ? ppmx 1 hour =??? ppm

51 Confidence Limits C / PEL = Y LCL = y - SAE UCL = y + SAE

52 Confidence Limits LEAD 54 / 50 = = = 1.2

53 Beware the PEL If above the PEL are you definitely getting sick? If you’re below the PEL are you definitely safe? Why or why not?

54 Thank You. Any Questions?


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