Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Toxic Effects, Nickel and Inorganic Compounds


Related Terms

  • Elemental Nickel Poisoning
  • Nickel Carbonyl Exposure
  • Nickel Catalyst Poisoning
  • Nickel Salts Exposure
  • Nickel Tetracarbonyl Exposure

Differential Diagnosis

  • Metal fume fever

Specialists

  • Dermatologist
  • Medical Toxicologist
  • Pharmacologist
  • Preventive Medicine Specialist

Comorbid Conditions

Factors Influencing Duration

Absorbed dose is the primary determinant of severity of toxic effects. The levels and length of time exposed, method of exposure (skin contact, inhalation, ingestion), organ systems involved, immediacy of treatment, and individual's response to exposure and treatment will determine the length of disability. Other factors influencing disability include pre-existing disease, age, pregnancy, and allergies, all of which affect individual susceptibility to the toxic effect of chemical exposures.

Medical Codes

ICD-9-CM:
985.8 - Toxic Effect of Other Metals, That From All Sources Except Medicinal Substances, Other Specified Metals; Brass Fumes; Copper Salts; Iron Compounds; Nickel Compounds

Overview

Nickel is a naturally occurring silvery metal found in the earth's crust in the form of nickel-containing minerals. Elemental nickel is recovered from mined ore and from scrap metal. Nickel is ubiquitous in industry. It is used in the manufacture of steel and many alloys, dyes, paints, and magnetic tapes. It is also found in diesel fuel. Nickel is used in electroplating, in nickel-cadmium batteries, and in ceramics and jewelry manufacture.

Contact dermatitis, usually due to nickel hypersensitivity, is the most common manifestation of exposure to soluble nickel compounds. Nickel is a common cause of skin allergy in the general population, causing redness and vesicles at points of contact in sensitized individuals. Chronic eczematous dermatitis involving the hands and arms may develop in nickel workers, particularly in electroplating shops where there is exposure to liquids and aerosols. Exposure to high levels of aerosols can also cause inflammation of the nose and sinuses, decreased sense of smell, and nasal septal perforation. Airborne nickel may cause an illness resembling metal fume fever.

Manufacture of pure nickel is particularly hazardous because of the potential exposure to the gaseous intermediate nickel carbonyl, the most toxic form of nickel. Workers engaged in the production, fabrication, or welding of nickel alloys may be exposed to nickel dust and fumes. In electroplating shops, workers may have respiratory and skin exposure to soluble nickel salts.

Studies of workers in nickel refineries have shown increased rates of lung and nasal cancers. These workers were exposed to a variety of nickel compounds in addition to other metals such as arsenic and a variety of irritant gases. As a result, it is difficult to determine which nickel compound(s) were the likely carcinogens. After considering this, the Environmental Protection Agency (EPA) has classified nickel refinery dust and nickel subsulfide as human carcinogens. Metallic nickel is also classified as a possible human carcinogen. The International Agency for Research on Cancer (IARC) has drawn the same conclusions classifying nickel compounds as carcinogens and nickel as a possible carcinogen.

Incidence and Prevalence: Nickel is the most common cause of allergic contact dermatitis, but no specific statistics are kept on nickel poisonings. Respiratory cases are often reported as metal fume fever. According to the 2002 annual report of the American Association of Poison Control Centers, there were 884 reported cases of metal fume fever, with no reported deaths (Watson 353).

Nickel workers have a 5 times greater likelihood of developing lung cancer and a 150 times greater risk of developing nasal cancer. Rates of laryngeal cancer are also increased.

Source: Medical Disability Advisor



Causation and Known Risk Factors

More women than men develop allergic contact dermatitis from exposure to nickel. There is no predisposition to poisoning by inhaled or ingested nickel based on age, sex, or race. More men than women develop cancer related to nickel exposure because of the demographics of miners and refinery workers.

Source: Medical Disability Advisor



Diagnosis

History: Because the symptoms in mild respiratory nickel exposure are initially nonspecific, work history or other history of exposure is an important diagnostic tool. Individuals with hypersensitivity to nickel will complain of an uncomfortable red rash at the point of contact, often on the hands and arms. Individuals who have been exposed to nickel fumes or dust may complain of headache, fatigue, drowsiness, nausea, and vomiting. These symptoms usually resolve when the individual is removed from exposure. In severe cases, after a delay of hours to days, the individual may complain of cough, chest pain, and fever. Difficulty breathing marks the development of diffuse interstitial pneumonitis, which may progress to adult respiratory distress syndrome (ARDS). Delirium, seizures, and coma may occur prior to death.

Physical exam: Individuals with allergic contact dermatitis present with a red rash.

Tests: The diagnosis of nickel hypersensitivity can be confirmed by patch testing. In evaluating individuals who have been exposed to nickel carbonyl, urine nickel levels greater than 100 mcg/L indicate moderate exposure, whereas levels greater than 500 ug/L indicate severe exposure. Cancer and precancerous conditions are confirmed by tissue biopsy.

Source: Medical Disability Advisor



Treatment

Nickel dermatitis is treated with topical steroids and removal from further exposure. Sensitized workers will usually need to transfer to jobs where there is no potential exposure. Respiratory tract irritation usually will resolve after removal from exposure. Individuals with significant exposure to nickel carbonyl should be admitted to the hospital to be monitored for the development of pulmonary complications and systemic toxicity. Prompt administration of the chelating agent dithiocarbamate may be helpful when urinary nickel levels are greater than 100 mcg/L.

Source: Medical Disability Advisor



Prognosis

Absorbed dose is the primary determinant of the severity of toxic effects. The prognosis depends on the extent and duration of exposure, although most exposures resolve completely. In severe exposures to nickel carbonyl, overwhelming pneumonitis may cause adult respiratory distress syndrome and death. The prognosis for nickel-induced cancer is related to the location of the cancer and the time of detection after onset.

Source: Medical Disability Advisor



Complications

Exposure to nickel carbonyl may cause pneumonitis, encephalopathy, acute respiratory distress syndrome, seizures, coma, and death.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Prevention is the best way to avoid the toxic effects of nickel.

The Occupational Safety and Health Administration's (OSHA) permissible exposure limit (PEL) time-weighted average (TWA) is 1 mg/cubic meter (does not apply to nickel carbonyl).

The National Institute of Occupational Safety and Health's (NIOSH) recommended exposure limit (REL) time-weighted average (TWA) is 0.015 mg/cubic meter, and it is considered to be a potential carcinogen (causes cancer) (does not apply to nickel carbonyl).

The threshold limit value (TLV) time-weighted average (TWA) is 0.5 mg/cubic meter as a confirmed human carcinogen.

The EPA recommends a lifetime nickel concentration limit of 0.1 mg/L of drinking water. The World Health Organization (WHO) recommends 0.02 mg/L.

The individual must have access to information about the health effects of nickel exposure in the workplace. Respirators, air filters, and protective clothing and eyewear may be needed. Length and levels of nickel exposure in the workplace must be monitored. The individual may need special training to handle nickel compounds.

Source: Medical Disability Advisor



Failure to Recover

If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.

Regarding diagnosis:

  • Has diagnosis of toxic effects of nickel been confirmed?
  • Is there a positive history of nickel exposure in the workplace?
  • Is the exposure dose within the range of doses believed to cause such effects?
  • Is the clinical illness, including the history, physical examination, and laboratory findings, consistent with other case descriptions?
  • Are the blood and urine levels of nickel at or near the normal value?
  • Is the timing between exposure and clinical onset compatible with the known biologic facts about the hazard?
  • Has individual experienced any complications?
  • Is individual allergic to nickel?
  • Does individual have an underlying condition that may affect recovery?

Regarding treatment:

  • Did individual receive prompt, appropriate treatment?
  • Have symptoms persisted despite treatment?
  • What other treatment options are available?

Regarding prognosis:

  • Are there special attributes of the particular individual that make it more or less likely that he or she would be so affected?
  • Could nickel exposure be occurring outside the workplace, such as in the home, in the community, or in recreational activities?
  • Has individual recently worked in another organization where nickel exposure is higher?
  • If occupational duties put individual at risk of exposure, is protective gear provided?
  • Has individual been instructed in its proper use?

Source: Medical Disability Advisor



References

Cited

Watson, William A., et al. "2002 Annual Report of the American Association of Poison Control Centers Toxic Exposure Surveillance System." American Journal of Emergency Medicine 21 5 (2003): 353-421.

Source: Medical Disability Advisor






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