Workplace Chemical Hazards & Occupational Skin Disease
How can chemicals affect the skin?
In many jurisdictions occupational skin disease represents the largest proportion of Occupational Disease and Workers Compensation Insurance claims. It affects workers is a wide range of industries. Chemicals encountered in the workplace may cause injury, irritation, sensitisation, infection, discoloration or other changes in the skin of the exposed worker. Some chemicals can even induce cancerous changes in the skin. Occupational dermatoses include these abnormalities of the skin resulting directly from, or aggravated by, the work environment. Sometimes the skin disease is so bad that an employee cannot work or carry out their usual activities at home.
Chemical Agents that Cause Occupational Skin Disease & Disorders
Chemical agents are the main cause of occupational skin diseases and disorders. These agents are divided into two types: irritants and sensitizers. Chemicals can directly irritate the exposed skin. Strong irritants (which may also be corrosives), such as nitric acid and sodium hydroxide (caustic soda), cause changes in the skin quickly, while mild irritants, such as alcohol and soap, may take several days to produce effects.
Some chemicals can sensitise the skin by altering the skin's reactivity through stimulating allergic responses so that even a slight subsequent exposure to the chemical may cause an allergic reaction in the skin.
A worker’s skin may be exposed to hazardous chemicals through direct contact with contaminated surfaces, deposition of aerosols, immersion, or splashes.
How are chemicals absorbed into the skin?
Dermal absorption is the transport of a chemical from the outer surface of the skin both into the skin and into the body. Studies show that absorption of chemicals through the skin can occur without being noticed by the worker, and in some cases, may represent the most significant exposure pathway. Many commonly used chemicals in the workplace could potentially result in systemic toxicity if they penetrate through the skin (i.e. pesticides, organic solvents). These chemicals enter the blood stream and cause health problems away from the site of entry in other areas of the body.
How do chemicals inflame and irritate the skin?
Occupational dermatitis is the most common work-related skin disorder. Contact dermatitis is a local inflammation of the skin caused by an allergy or irritation due to being in contact with certain substances. The skin becomes red, itchy, and can blister. Pain, heat and swelling can occur with an outbreak.
There are about 3,000 substances that are recognized as contact allergens.
The 2 types of occupational contact dermatitis include irritant dermatitis that makes up about 80% of contact dermatitis, the other 20% is allergic dermatitis.
Both irritant and allergic contact dermatitis can occur together, and it is not uncommon for an employee to be exposed to several irritants and sensitizers simultaneously.
An irritant contact dermatitis may also develop first, rendering the skin more susceptible to penetration by sensitizers. It is also possible that an original allergic contact dermatitis might be later sustained by an irritant.
Here are some examples of how the skin is damaged by an irritant:
- Detergents, soaps and repeated hand washing can remove the protective oily layer of the skin and leave it exposed to damage.
- Physical damage such as friction or minor cuts from fibre glass can breakdown the protective layer and allow substances to enter.
- Chemicals such as acids or alkalis can burn the outer layer of the skin.
Examples of chemical irritants:
- Solvents and degreasers
- Working with wet cement
- Cutting oils
- Personal care products, such as soaps, deodorants and cosmetics
- Airborne substances, such as sawdust or wool dust
How do chemical corrosives damage the skin?
Chemical corrosives are irritants that are so strong that they produce immediate destruction of the skin. They include hydrofluoric and chromic acid, strong solutions of hydrochloric, nitric and sulphuric acid, strong ammonia and sodium hydroxide (caustic soda) solutions, chloride of lime and phenol. Other strong irritants include corrosive organic acids, corrosive salts, reducing agents, petroleum oils, solvents, tar and pitch. Examples of skin corrosives include:
- Corrosive organic acids
- Corrosive salts
- Reducing agents
- Petroleum oils
- Tar and pitch
What is a chemical skin sensitizer?
Allergic contact dermatitis is an allergic response to skin contact with some allergy-causing material. In allergic dermatitis the rash can occur in areas of the skin not in direct contact with the substance. Workers become sensitised days to months to years after initial contact with a substance. Once the individual becomes sensitised, each time the person comes into contact with the sensitising substance, even in very small amounts, dermatitis will develop. The long-term health consequences and ability to remain at work can be significant. Once sensitised a person is likely to remain so for life.
Common sensitizers that can cause an allergy include chromates found in cement, nickel found in cheap jewelry, epoxy resins, formaldehyde, wood dust, flour, printing plates and adhesives.
What are carcinogens that target the skin?
Skin cancer due to occupation is more common than is generally recognized and often shows up years after the occupational exposure. Workers can get skin cancer from exposure to chemical carcinogens, physical burns, and radiation. Skin cancer is the uncontrolled growth of abnormal skin cells. It occurs when unrepaired DNA damage to skin cells (most often caused by ultraviolet radiation from sunshine or tanning beds) triggers mutations, or genetic defects, that lead the skin cells to multiply rapidly and form malignant tumors. Examples of Carcinogens that target the skin:
- Polycyclic hydrocarbons (tar, pitch, shale and mineral oils ore derivatives like creosote)
- Coal tar hydrocarbons
- Arsenic or arsenic based compounds
- Ionizing radiation such as X-Rays
- Saps and fine dusts from wood