Published on January 16, 2014
The Aging Worker: Exposures to Chemicals, Physical and Infectious Agents Presented by: Ron Pearson, M.S., CIH Environmental Health & Safety, Inc. 1
Today’s presentation Will focus on Occupational Health related to aging and: Chemical exposures Noise exposures Heat stress It will not address: Ergonomic issues Cognitive issues and mental health Visual changes
Today’s Presentation: Part Part Part Part 1 2 3 4 - Definitions and Trends Chemical Exposures Physical and Infectious Agents Management Issues
Part 1 - Definitions and Trends
What is an “Aging Worker”? It depends on whom you ask… Some sources say > 40 years old Most say > 45 years old Some prefer groupings such as: ‘Younger’ aging worker: 45-54 45‘Middle’ aging worker: 55-65 55‘Older’ aging worker: >65
Some facts... Older workers have: low workplace injury rates (highest rates are among workers 25-44) 25fewer work absences low turnover rates Why? increased experience, safer behaviors, less physically demanding jobs 6
But ... Older workers have higher fatality rates, from: homicides car accidents falls struck by objects 7
Some Trends in the U.S.... Declining birthrates The percentage of the workforce above age 55 is increasing 8
% of workers > 65 in the labor force 30 ? 20 % 10 1950 1960 1970 1980 1990 2000 2010 By 2020, 30% of the U.S. population will be over 55
As we age, some things decrease.. Pulmonary function (oxygen absorption, carbon dioxide elimination) Cardiac function Immune system functionality Activity of some liver enzymes and blood flow Kidney filtration rates and blood flow Hearing ability Ability to regulate body heat 10
And some things (unfortunately) increase…. Cardiovascular diseases hypertension (high blood pressure) atherosclerosis (hardening of the arteries) arrhythmia (abnormal heart rhythms) Cancer rates Chronic Obstructive Pulmonary Disease Diabetes Neurological diseases
Causes of death - Ages 65-74 65Cancers Cardiovascular diseases Respiratory diseases Other © Env. Health & Safety, Inc., 2009 12
Part 2 - Chemical Exposures
Chemical exposures and the aging worker Very few environmental chemicals have been tested for toxicity in the elderly In most cases, deficits relate more to lifelifestyle and diseases than to the aging process per se (lack of exercise, eating and drinking habits, alcohol consumption, smoking) However, increased susceptibility must be considering when managing exposures to chemical, physical and infectious agents 14
R Application of the TLVs “There are numerous possible reasons for increased susceptibility to a chemical substance, including age, age, gender, ethnicity, genetic factors (predisposition), lifestyle choices (e.g., diet, smoking, abuse of alcohol and other drugs), medications, and medications, prepre-existing medical conditions (e.g., aggravation of asthma or cardiovascular disease).” © Env. Health & Safety, Inc., 2009
Loss of sense of smell Has profound safety implications for certain situations where chemical warning properties are critical High prevalence of atrophy of olfactory senses reduces ability of many older people to detect low concentrations of chemicals Example: Street maintenance workers entering confined spaces with hydrogen sulfide 16
Chemicals that are poorly metabolized - Group 1 Absorbed and distributed into tissues according to “partitioning behavior” Example: Agricultural workers exposed to organochlorine compounds (e.g some pesticides), which concentrate in adipose (fat) tissue During weight loss, adipose tissue is mobilized and accumulated chemicals are liberated into body fluids. 17
Chemicals that are poorly metabolized - Group 2 Poorly excreted, and accumulate in the body Some are detoxified by binding to specific proteins, resulting in long-term storage longExample: Welders exposed to heavy metals such as cadmium - toxicity among workers over 50 may be related to the decreased capacity of metallothionein synthesis with advancing age (which normally help in detoxification of heavy metals) 18
Lung Toxicants Air contaminants can be metabolized to “reactive intermediates” and damage cells Can cause severe adverse effects on older workers with weak defense mechanisms chronic effects such as COPD (Chronic Obstructive Pulmonary Disease) Example: Auto or fleet maintenance mechanics - exhaust gases Example: Maintenance workers exposed to irritant gases from torch cutting or welding 19
WorkWork-related Asthma Best estimates suggest ~ 15% of asthma cases are related to work exposure Wide variety of causal agents - epoxies, acrylates, wood dusts, formaldehyde As workforce ages, so will number of asthma cases Differentiation between COPD and asthma is complicated
Neurotoxins Manganese can cause rigidity and tremors resembling Parkinson's disease Example: Metal workers using inertinertgas welding (e.g. MIG, TIG) may be exposed to high levels of airborne manganese fume 21
General Toxicants Carbon Monoxide Older workers are more susceptible to the effects of carbon monoxide due to cardiac insufficiency Blood COHb (carboxyhemoglobin) is a carboxyhemoglobin) biomarker of exposure - values of about 5% for an average adult performing light work for 6 to 8 hours at 35 ppm Studies have shown a reduction in the length of time to the onset of angina in men with stable angina pectoris
Carbon monoxide - continuedcontinuedTLV(R) is set at 25 ppm to prevent COHb from exceeding 3.5% Example: Older forklift operators chronically exposed to levels of carbon monoxide below occupational exposure limits may still cause adverse health effects ASHRAE recommends a limit of 9 ppm in its Indoor Air Quality standard (62)
Regulatory Issues: Methylene Chloride Federal OSHA Standard puts a specific age requirement on medical surveillance For employees < 45 years, every three years For employees > 45 years, every year
Regulatory Issues: Methylene Chloride Preamble to the Federal OSHA Standard: “... it is ... more likely that employees 45 years and older would experience the adverse cardiac effects of MC exposure. Three-year intervals Threebetween physical examinations for workers younger than 45 seemed the proper interval to balance the conservation of valuable medical resources and the provision of a medical surveillance program that is useful for detecting adverse MC health effects.”
Medical Diagnoses Issues A 1991 Study (Landrigan and Baker) estimated that there are 50,000 to 70,000 deaths yearly from workplace diseases, and; These are typically not correctly diagnosed because they mimic nonnonoccupational illnesses or disorders, and; Most physicians are not adequately trained to recognize them.
Part 3 Physical and Infectious Agents
Noise and Hearing Loss Older workers lose ability to distinguish high frequencies (presbycusis) Decreased speech intelligibility (can’t distinguish consonants) Management responses - will be discussed later in Management section 28
Heat Stress WBGT (web bulb globe temperature) nomographs are typically how work regimens are established in hot, humid weather Older workers are less able to maintain normal temperature because they: have decreased peripheral blood flow, and; start sweating later They are at an increased risk for heat stroke (which is a life-threatening emergency) life-
Infectious Agents Immunodeficiency among elderly is wellwell-documented - presents greater susceptibility to some infectious agents Example: HVAC maintenance technicians and exposure to legionella in water supplies (e.g. cooling towers) potential to develop Legionnaire’s disease 30
Part 4 - Management Issues
Why should we want to keep older workers in the labor force? Very good productivity Work ethic, loyalty, dedication Job experience Knowledge, including basic skills in reading, writing, and math Availability
How should industry respond? Management needs to be careful to respond not to just the ‘squeaky wheels” Older workers are most likely to raise complaints about sensory issues - ‘too cold’, ‘too dim’, etc. They are unlikely to be aware of more serious health threats from ‘silent’ chemical exposures until it is too late
How should industry respond? Company managers need to anticipate and prepare for ways to prevent occupational health issues among older workers Recognition of age-related diseases (e.g. agediabetes) is needed to prevent confusion with other work-related causes (e.g. workperipheral neuropathy) Most older workers are unlikely to ‘self‘selfregulate’ their activities to accommodate their own need 34
How should industry respond? Administrative Changes Rotating staff to minimize chemical and/or noise exposures Assessment of hearing loss - may need to modify evaluation protocols Assigning younger workers to work outdoors in very hot/humid weather Training - training older worker to be aware of their own physical limitations 35
How should industry respond? Engineering Changes Upgrading exhaust ventilation (to eliminate need for respirators) Improving noise controls Modifying warning systems (e.g. existing audible alarms) compensate for existing hearing loss by using other senses - e.g. add vibratory or visual alarms - or lowering ‘pitch’ (frequency) (frequency) 36
How should industry respond? Medical Surveillance and PPE Programs Assessment of respirator use abilities - may need to modify medical screening protocols Be aware of differentiating medical screening requirements for older workers (e.g. methylene chloride) Prescription safety glasses - consider providing this option to all workers > 50 37
Future Trends Occupational Exposure Limits may be set with a new sub-category for older subworkers More research is definitely needed to quantify risks and further define control options
Resources International Program on Chemical Safety: Environmental Health Criteria 144 - “Principles of evaluating chemical effect on the aged Population” “Health and Safety Needs of Older Workers”, National Academies Press (available on NIOSH website)
Why should a workplace look at issues concerning aging workers? Who is considered to be an older worker? Do aging workers need any special accommodations?
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