Chemical Agents

Crude oil is a complex chemical mixture with many hazardous components. Workers could be exposed during drilling, pumping, and transportation of crude, as well as during equipment maintenance. Liquid crude can irritate the skin and eyes. Prolonged contact can cause drying and cracking of the skin, which can be painful. Hot fluids can cause severe burns. Vapours can affect the central nervous system, initially causing dizziness or drowsiness (a safety hazard in operational areas). Inhalation effects could progress to unconsciousness or death. The International Agency for Research on Cancer (IARC) considers crude oil to be "not classifiable as to its carcinogenicity to humans"; however, crude contains benzene, a known human carcinogen.

Natural gas extracted from the field typically contains "light hydrocarbons". In addition to being highly flammable, methane, ethane and propane are asphyxiants – that is, they can displace oxygen. This is especially important to be aware of in confined spaces, as these gases can create an oxygen-deficient environment. Butanes can be anesthetic - causing dizziness, headaches, or impaired judgment. The gas stream will also contain benzene (a known carcinogen) and other volatile organics.

Poisonous hydrogen sulfide gas (H2S) can be present in both crude oil and natural gas. Furthermore, it can be released in fatal concentrations during normal field activities.

In addition to these naturally occurring substances, a wide range of commercial chemicals are used by the oilfield service industry. Each will pose its own hazards, which should be disclosed on its material safety data sheet.

Biological Hazards

These may not be directly related to operational tasks in the oil and gas industry, but biological hazards could be present in buildings or other areas.

Hantavirus can be carried in the droppings, urine, or saliva of rodents – particularly deer mice. Buildings, sheds and other areas where rodents may nest should be considered as potential sources of hantavirus. Human exposure can result when contaminated dust and dirt becomes airborne. The virus could also enter the body through broken skin or through eye contact. Although hantavirus is not frequently transmitted to humans, its effects can be serious when it is transmitted. Severe respiratory illnesses and deaths have been caused by hantavirus.

Various species of mould can flourish in wet or moist environments. Buildings that are affected by condensation, flooding, water leaks or excessive humidity may develop mould problems. People with asthma, mould sensitivity or other immune disorders are most susceptible to the ill effects of mould exposure.

Physical Agents

Noise levels often exceed regulated limits. Drilling, production and well servicing tasks generate extremely high noise levels that can damage hearing. Permanent hearing loss is a very real risk.

Cold weather is also part of the oilfield workplace. Cold environments rob body heat. Gone unchecked, excessive cold can result in:

• frostbite – freezing of body tissue,
• hypothermia – significant reduction of the body’s core temperature (potentially fatal), or
• trench foot – swelling and internal bleeding caused by continuous immersion of the feet in very cold water.

Prolonged periods of work in the cold can also increase the risk of back injury and can reduce one’s ability to concentrate on critical job tasks.

NORM – Naturally Occurring Radioactive Material – includes radium, radon gas, and radon decay products. Equipment used in oil and gas production and gas processing operations can become contaminated with NORM. Scales, sludges and dusts contaminated with NORM can cause skin burns (radium) and an increased risk of lung cancer and leukemia.

Evaluation and Control

The severity of health effects from exposure to chemical, biological and physical agents depends on the dose. As with other oilfield hazards, their risks can be eliminated or reduced through a program of hazard assessment and exposure management.