Industrial Hygiene. Introduction to Industrial Hygiene ENVIRONMENTAL SCIENCE

Transcription

1 Introduction to Industrial Hygiene Environmental Safety and Health ENVIRONMENTAL SCIENCE is the study of how the parts of nature and human societies operate and interact. is devoted to the control of biological, chemical and physical agents in the environment to prevent adverse effects, such as, air and water pollution, destruction and depletion of natural resources and loss of biodiversity. In IH, the environment is the workplace and we seek to prevent adverse effects in humans. Industrial Hygiene is the science and art devoted to the anticipation, recognition, evaluation, and control of environmental factors and stresses arising in or from the workplace that may cause sickness, impair health and well being, discomfort or inefficiency among workers, their families or members of the community at large.

2 1. ANTICIPATION Foresee work hazards before they exist and take action to prevent their occurrence. Get involved in the design phase Anticipate conditions changing Know history; if it happened before, take measures to prevent reoccurrence Keep up with the literature, scientific developments, codes and legislation 2. RECOGNITION Be familiar with the process and work operations Maintain an inventory of agents Periodic review of job activities Evaluate the effectiveness of control measures Conduct technical audits and evaluations Review the health status of workers Can obtain information from texts, company reports and records, making observations and asking questions. Some Definitions

3 Hazard Potential to cause harm under specified operating conditions and depends on: nature of the process how the material is handled and the quantity training, expertise and work habits of employees extent of containment, enclosure, ventilation control to contain, dilute or remove the hazard from the work zone. Toxicity It is a biological property of an agent and describes the degree of undesirable effects. A given dose will produce predictable effects. The dosing regimen and other factors may modify the extent of the effects observed. Toxicological Note All substances are poisons; there is none which is not a poison. The right dose differentiates a poison and a remedy

4 Dose = Concentration x Time A given dose should produce a predictable response. Response can be modified by: Route of exposure (inhalation, dermal, ingestion, injection, Occular) Time allowed for detoxification and repair mechanisms Time Dose regimen Acute Chronic Individual sensitivity Physiological Classification of Contaminants Irritant Asphyxiant Simple Chemical Anesthetic Teratogen Carcinogen Sensitizer Systemic poisons Nephrotoxic Hepatotoxic Hematopoietic Fibrotic dusts Stresses Biological - bacteria, viruses, fungi, parasites, insects, pollens, grain and wood dusts, sewage, animal danders. Physical - noise, ultrasound, vibration, pressure, ionizing and non-ionizing radiation, illumination, heat, cold, electrical energy and mechanical forces. Ergonomic stresses occur at the man - machine interface that result in mental or physical errors, fatigue, or strain. Repeated or forceful movements, poor lighting and shiftwork.

5 Stresses - Chemical Gas physical state of matter; formless fluids that expand to occupy a space Vapor gaseous state of material that is normally liquid or solid Aerosol anything suspended in air Dust solid particles produced mechanically by grinding or abrasive action Fume fine solid particles (<1μm) from condensation of vaporized solid substance; hot processes; oxides Stresses - Chemical Mist large liquid particles from splashing or agglomeration of a fog Fog fine liquid particles from condensation of a vaporized liquid Smoke liquid and solid particles from incomplete combustion Smog smoke + fog; air pollution haze Fiber solid particle, length is at least 3 times the width Ash incombustible minerals Units of Concentration Dusts and Liquids weight/volume basis mg/m 3 milligrams per cubic meter μg/m 3 micrograms per cubic meter mppcf millions of particles per cubic foot f/cc fibers per cubic centimeter

6 Flammable (Explosive) Range Lower Flammable Limit (LFL, LEL) is the minimum concentration of gas or vapor in air that will ignite in the presence of an ignition source. If lower, too lean to support combustion. Upper Flammable Limit (UFL, UEL) maximum concentration that will support a flame; if higher, too rich. 3. EVALUATION is a continual process of observation, measurement and judgment of the existing environmental conditions. Determine if an agent is present in the workplace Hypothesize an exposure level Design a survey Sampling and analysis Compare results with standards and guidelines Make a judgment on hazard and risk Communicate your judgment of the results with the individuals affected and those in authority to remedy the situation. Purpose of Sampling often dictates part or all of the sample strategy and techniques to be used. to measure exposure levels: For health and safety evaluations Effectiveness of control measures Monitor process changes; warn of hazardous conditions Investigate complaints Comply with standards

7 REPRESENTATIVE SAMPLING One cannot measure everybody all the time, therefore use representative sampling. Measure part of the environment and infer things about the totality. Where, Whom, Kind of Sample, Duration, Number Note Worker and Process Activity Observe worker during sampling Avoid making statements on presumed results Avoid interfering with work activity Recognize the Hawthorne Effect, that observed employees tend to perform in a non-routine manner Keep records and maintain a Chain of Custody Biological Monitoring Measures the material, a metabolic product or change in metabolic production due to exposure dose. Sample body fluids or tissue (breath, urine, blood, hair) for a biomarker. Used to document the absorbed dose, detoxification and elimination after an exposure incident. Used to identify sensitive individuals, poor work habits, inadequate controls, and efficacy of PPE. Used for agents that are absorbed through the skin. The individual is the monitor.

8 Other Monitoring Surface Wipes can be used to measure contamination of work surfaces, tools, gear, clothes, rest areas, and skin. Medical Monitoring - Physician measures the body's response, checking for effects (pulmonary function, blood counts, x-rays). By the time they are detected, functional loss may be significant. COMPARE RESULTS WITH STANDARDS TWA - Time Weighted Average STEL - Short Term Exposure Limit Ceiling - Value that cannot be exceeded even momentarily Excursion Limit - 3x TLV-TWA for 30 minutes are allowed, but no intermittent exposures at 5x TLV-TWA COMPARE RESULTS WITH STANDARDS NIOSH - National Institute for Occupational Safety and Health REL - Recommended Exposure Limit IDLH - Immediately Dangerous to Life and Health; 30 minutes of exposure will not cause escape impairing symptoms. OSHA - Occupational Safety and Health Administration PEL - Permissible Exposure Limit - Law

9 OSHA must consider: Economic impact and feasibility Analytical detection limits Societal values of acceptable risk The limit must be shown to substantially reduce significant risk of material health impairment TLVs and BEIs TLVs are Threshold Limit Values for Chemical Substances and Physical Agents. BEIs are Biological Exposure Indices for Chemical Substances. TLVs Airborne concentrations of chemical substances in the workplace Nearly all workers may be repeatedly exposed day after day without adverse health effects. Guidelines; not fine lines between safe and dangerous concentrations.

10 TWA, C, STEL Time Weighted Average [TWA] for 8-hour workday, 40-hour week. CEILING [C] concentration that should never be exceeded. Short Term Exposure Limit [STEL] 15 min TWA Exposures above TLV TWA up to STEL: not longer than 15 min not more than 4 times/day at least 60 minutes between successive exposures ACGIH CARCINOGEN CLASSIFICATION A1 Confirmed human carcinogen A2 Suspected human carcinogen A3 Confirmed animal carcinogen with unknown relevance to humans A4 Not classifiable as a human carcinogen A5 Not suspected as a human carcinogen IF NO DATA EXISTS, COMPOUND REMAINS UNCLASSIFIED Total Particulates NIOSH Method mm cassette

11 IOM Inhalable Dust Sampler 25mm Filter, 2 L/min Controls 1. Elimination 2. Substitution 3. Engineering 4. Administrative 5. PPE

12 Proof of adequate control monitoring data that demonstrates exposures are consistently less than the OELs.