Course 150 - Physical Health Hazards in Construction

Environmental and Ergonomic Hazards

Noise Hazards

Noise, or unwanted sound, is one of the most pervasive occupational health problems. Exposure to high levels of noise causes hearing loss and may cause other harmful health effects as well. The extent of damage depends primarily on the intensity of the noise and the duration of the exposure. Exposure to high levels of noise is accumulative and can cause permanent hearing loss. Neither surgery nor a hearing aid can help correct this type of hearing loss. Construction sites have many noisy operations and can be a significant source of noise exposure.

OSHA requires employers to monitor noise exposure levels in a way that accurately identifies employees exposed to noise at or above 85 decibels (dB) averaged over 8 working hours, or an 8-hour time-weighted average (TWA). Employers must provide hearing protectors to all workers exposed to 8-hour TWA noise levels of 85 dB or above. This requirement ensures that workers have access to protectors before they experience any hearing loss.

2-3 Foot Rule and Noise Indicator

When a sound level meter is not available, you should use the 2-3 foot rule: Stand about an arm's length away from your coworker: If you have to raise your voice to be heard 2-3 feet away, you should assume the sound level is at or above 85 dBA.

A personal noise indicator is a warning device. It indicates if your immediate exposure is less than or greater than 85 dBA. It flashes green if the sound level is under 85 dBA and red when above 85 dBA.

1. At what point is the employer required to provide hearing protection for workers?

a. When noise is above 80 dB for at least one workday
b. When OSHA recommends hearing protection during an inspection
c. When noise is at or above an average of 85 dB over 8 hours
d. When the noise level is above 90 dB for any length of time

Probable Noise Levels of Construction Equipment

Equipment and daily activities at construction job sites can expose workers to high levels of noise. Sound levels on the chart below are listed in decibels (dBA) – the larger the number, the higher the volume or decibel level. How loud the noise is (volume), how long the noise lasts, and how close you are to the noise are all important in determining the hazard.

The table below takes a look at the sound levels of common equipment and tools on a construction site.

Equipment or Tool Noise Level May Exceed (decibels)
Backhoe 85
Bulldozer 87
Chopsaw 92
Grader/Scraper 107
Front End Loader 90
Jackhammer 85
Nail Gun 97
Router 90
Welding Equipment 92
Source: University of Washington Department of Environmental & Occupational Health Service-July 2005.

For more information on hearing conservation, see course 751 Hearing Conservation Program.

2. Which of the following is NOT a consideration when determining noise hazards?

a. The purpose of the noise
b. How long the noise lasts
c. How loud the noise is
d. Distance from the noise source

Whole Body Vibration

vibration

Whole-body vibration, from driving trucks or operating subways, can affect skeletal muscles and cause low-back pain. Symptoms include:

  • low back pain, and
  • shooting pain or numbness in the upper legs.

Whole-body vibration can occur from operating large mobile equipment, such as the following:

  • drillers
  • air hammers
  • pile drivers
  • tractors
  • graders
  • excavators
  • earth-moving equipment
  • other large equipment

3. What are the symptoms of overexposure to whole body vibration?

a. Dizziness and fatigue
b. Low back pain and shoot pain or numbness in upper legs
c. Low back pain and numbness in the hands
d. Headache and upper back stiffness

Hand Vibration

disc grinder

Hand and arm vibration can result from using hand-held power tools, such as sanders, chippers, pneumatic drills and hammers, and disc grinders.

  • Raynaud's Syndrome (white finger). This condition occurs when blood vessels of the hand are damaged from repeated exposure to vibration for a long period of time. The skin and muscles do not get the necessary oxygen from the blood and eventually die. Symptoms include intermittent numbness and tingling in the fingers; pale, ashen, and cold skin; eventual loss of sensation and control in the hands and fingers.
  • Using vibrating tools may also result in fatigue, pain, numbness, increased sensitivity to cold, and decreased sensitivity to touch in fingers, hands, and arms.

Here are some points to remember to make sure power tools minimize vibration being transmitted to the hands:

  • Tool maintenance should be performed on a regular basis.
  • Oiling and cleaning tools daily increases the life of the tool and reduces vibration.
  • Out-of-balance or off-center grinding wheels, pads, and spindles are major contributors to vibration.
  • Some tools use auto-balancing technology to compensate for off-center pads/wheels.
  • Tools should be gripped as lightly as possible while still maintaining control of the tool.
  • Cold hands are more vulnerable to the effects of vibration.
  • Select anti-vibration gloves that minimize the loss of tactile sensitivity.
  • Many low vibration tools are commercially available, such as grinders, sanders, and impact wrenches.

4. If you feel numbness and tingling in your hand that uses vibrating tools, what condition might this indicate?

a. Trigger finger
b. De Quervain's disease
c. Raynaud's Syndrome
d. Carpal tunnel syndrome

Temperature Extremes

A change in body temperatures due to extreme work environmental conditions can lead to stress or illness from heat and cold. If not treated in time, both heat and cold stress can develop into life-threatening situations.

  • Heavy work in high temperatures can cause muscle cramps, dehydration, sudden collapse, and unconsciousness.
  • Cold temperatures can lead to fatigue, irregular breathing, confusion, and loss of consciousness (hypothermia).

The table below shows some common heat and cold injuries on a construction site.

Heat Illnesses Cold Illnesses/Injuries
Heat Rash Frost Nip
Fainting Immersion Injury (Trench Foot)
Heat Exhaustion Frostbite
Heat Stroke Hypothermia
Heat Cramps

5. Which of the following can cause muscle cramps, dehydration, sudden collapse, and unconsciousness?

a. Heavy work in high temperatures
b. Working outdoors in cold temperatures
c. Any work in uncomfortable environments
d. Working all day in a building that lacks air conditioning

Hot Working Conditions

Hot Enough for You?

The following conditions can occur if a worker is exposed to hot temperatures:

  • Heat exhaustion - can result in headaches, dizziness, light-headedness, weakness, mood changes, feeling sick to your stomach, pale clammy skin, vomiting, and fainting.
  • Heat stroke - leads to dry, pale skin, mood changes, seizure, collapse, and possible death.

Follow these safe work practices when working in hot temperature conditions.

hot temps
  1. Seek medical help for cold- and heat-related stresses.
  2. Lower the employee's body temperature in heat-related conditions.
  3. Perform work during the cooler times of the day.
  4. Use the "buddy" system (work in pairs).
  5. Drink plenty of cool water in warm, hot weather.
  6. Wear appropriate clothing (hat and light, loose-fitting, breathable clothing).
  7. Apply sunscreen on sunny days.
  8. Take frequent, short breaks indoors to cool off.
  9. Educate employees to recognize and seek medical help for workers that have symptoms of heat-related stresses.

6. If you see a co-worker fall to the ground and have a seizure on a hot day, it is most likely due to _____.

a. Heat stroke
b. Hyperthermia
c. Heat exhaustion
d. Dehydration

Cold Working Conditions

cold temps

Cold working conditions can also cause problems for construction workers. For example, rain, snow, sleet and other wet and windy conditions can be unbearable for extended periods of time.

The following conditions can occur if a worker is exposed to cold temperatures:

  • Frostbite is the freezing of deep skin tissue layers and leads to hardening and numbing of the skin. It usually affects the fingers, hands, toes, feet, ears, and nose.
  • Hypothermia occurs when the body's temperature falls below 95 degrees F. The person becomes tired and drowsy, begins to shiver uncontrollably, moves clumsily, and is irritable and confused. As the hypothermia progresses, the victim's speech becomes slurred, his or her behavior may become irrational, and unconsciousness and full heart failure can occur.

Follow these safe work practices when working in cold temperature conditions.

  1. Seek medical help for cold-related stresses.
  2. Raise the employee's body temperature in cold-related conditions to prevent the progression of symptoms.
  3. Schedule work during appropriate times of the day.
  4. Perform work during the warmer times of the day.
  5. Use the "buddy" system (work in pairs).
  6. Do not drink alcoholic beverages in cold weather.
  7. Drink warm beverages in cold weather.
  8. Wear appropriate clothing (warm, layered clothing, including hat and gloves). Pay special attention to protecting feet, hands, face, and head. Up to 40 percent of body heat can be lost when the head is exposed.
  9. Take frequent, short breaks to warm up.
  10. Avoid exhaustion or overworking, because energy is needed to keep muscles warm.
  11. Educate employees to recognize and seek medical help for workers that have symptoms of cold-related stresses.

7. If your co-worker's speech is slurred and behavior is irrational while working on a cold day, which condition should you suspect is the cause?

a. Frost Nip
b. Frostbite
c. Hyperthermia
d. Hypothermia

Radiation Exposure

cold temps
Sources of radiation exposure.

Radiation may be defined as energy traveling through space. The most familiar form of electromagnetic (EM) radiation is sunshine, which provides light and heat. Sunshine consists primarily of radiation in infrared (IR), visible, and ultraviolet (UV) frequencies. Lasers also emit EM radiation in these "optical frequencies."

  • Ionizing radiation: The higher frequencies of EM radiation, consisting of x-rays and gamma rays, are types of ionizing radiation.
  • Non-ionizing radiation: Lower frequency radiation, consisting of ultraviolet (UV), infrared (IR), microwave (MW), Radio Frequency (RF), and extremely low frequency (ELF) are types of non-ionizing radiation.

Radiation affects people by depositing energy in body tissue, which can cause cell damage or cell death. In some cases there may be no noticeable effect. In other cases, the cell may survive but become abnormal, either temporarily or permanently. An abnormal cell may become malignant.

Both large and small doses of radiation can cause cellular damage. The extent of the damage depends upon the total amount of energy absorbed, the time period and dose rate of the exposure, and the particular organs exposed.

  • Chronic exposure is continuous or intermittent exposure to low doses of radiation over a long period of time. Health effects are delayed and can include cancer and other health outcomes such as benign tumors, cataracts, and potentially harmful genetic effects.
  • Acute exposure is exposure to a large, single dose of radiation, or a series of moderate doses received during a short period of time. Large acute doses can result from accidental or emergency exposures or from specific medical procedures (radiation therapy).

Electromagnetic Spectrum

8. The extent of damage from radiation sources depends on which of the following factors?

a. The type of energy absorbed
b. The total amount of energy absorbed
c. The average over an 8-hour workday
d. The frequency of the radiation absorbed

Ionizing Radiation

ionizing
Ionizing radiation penetration.

Ionizing radiation is energy in the form of waves or particles that has enough force to remove electrons from atoms. The major types of radiation emitted during radioactive decay are alpha particles, beta particles, and gamma rays. Radiation can come from natural sources or man-made radionuclides. Man-made x-rays, another type of radiation, are produced outside of the nucleus.

  • Alpha particles are energetic, positively charged particles consisting of two protons and two neutrons. External exposure (external to the body) is of far less concern than internal exposure, because alpha particles lack the energy to penetrate the outer dead layer of skin.
  • Beta particles are fast moving electrons emitted from the nucleus during radioactive decay. Some beta particles can penetrate the skin and cause radiation damage, such as skin burns. However, as with alpha-emitters, beta-emitters are most hazardous when they are inhaled or ingested.
  • Gamma rays - Like visible light and x-rays, gamma rays are weightless packets of energy called photons. Gamma rays are a radiation hazard for the entire body. While gamma rays can easily pass completely through the human body, a fraction will always be absorbed by tissue.
  • X-rays are high-energy photons produced by the interaction of charged particles with matter. Literally thousands of x-ray machines are used daily in the medical and other industries for examinations, inspections, and process controls. Because of their many uses, x-rays are the single largest source of man-made radiation exposure.

Controlling Exposure

Basic Control Methods for external sources of ionizing radiation include:

  • Time: Minimize time of exposure to minimize total dose. Rotate employees to restrict individual dose.
  • Distance: Maximize distance to source to maximize attenuation in air.
  • Shielding: Minimize exposure by placing absorbing shield between worker and source.

9. Which of the following describes ionizing radiation?

a. Radiation that causes a static reaction in materials
b. Radiation that raises electrons one level within the atom
c. Radiation that has enough force to remove electrons from atoms
d. Radiation that causes atoms to combine and emit light

Non-Ionizing Radiation

non ionizing

Non-ionizing radiation refers to any type of electromagnetic radiation that does not carry enough energy to ionize atoms or molecules - that is, to completely remove an electron from an atom or molecule. Non-ionizing radiation is essential to life, but excessive exposures will cause tissue damage.

Non-ionizing radiation includes the spectrum of infrared (IR), microwave (MW), radio frequency (RF), and extremely low frequency (ELF) and ultraviolet (UV).

Lasers commonly operate in the UV, visible, and IR frequencies.

Non-ionizing radiation is found in a wide range of occupational settings and can pose a considerable health risk to potentially exposed workers if not properly controlled, including skin cancer, eye damage, premature skin aging, and burns.

Workers performing welding and cutting are routinely exposed to the ultraviolet (UV) radiation given off by an arc or flame which can injure their eyes. For protection from this UV radiation, welders must use personal protective equipment, such as safety glasses, goggles, welding helmets, or welding face shields.

10. Which of the following describes non-ionizing radiation?

a. Radiation with frequencies in the x-ray range
b. Radiation that results in nuclear fission
c. Radiation that has enough force to remove electrons from atoms
d. Radiation that fails to remove electrons from atoms or molecules

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