• Volatile Organic Compounds (VOCS)
  • Naturally Occurring Radioactive Material (NORM)
  • Diesel Exhaust


What’s the risk?

Exposure to silica is one of the most widespread OD risks. Repeatedly inhaling crystalline silica dust can cause silicosis, an incurable lung disease that resulted in 46,000 deaths globally in 2013. This is a chronic OD exposure, meaning that it can take many years before silicosis is identified as the cause behind a worker’s symptoms.

How are workers exposed?

Silica exposures may occur during the hydraulic fracturing processes used for oil and gas well development, including the following:

  • loading, unloading, transportation, and storing sand
  • cementing operations
  • abrasive blasting using sand that contains crystalline silica components, such as river sand

How can you reduce risk?

Use water mist for dust suppression and use amended water (e.g., containing chloride and magnesium salts) to reduce dust generation on roads into and at the well site.

Use a less hazardous non-silica proppant (e.g., ceramic and resin-coated).

Use local exhaust ventilation to capture and collect fugitive dust emissions.

Use passive enclosures at points of dust generation (e.g., install stilling curtains around the bottom sides of the sand movers).

Minimize distances between the transfer belt conveyors and blender hoppers.

Replace transfer belts with screw augers on sand movers.

Mandate the use of cam-lock caps for fill ports on sand movers.

Monitor workers to determine their exposure to crystalline silica (e.g., conduct breathing zone air sampling wherever workers are engaged in activities that use “frack” sand).

Use equipment with built-in dust collection systems that pass the material through a filtration system.

Require workers to wear NIOSH-approved respirators. If the respirators are tight-fitting, workers cannot have facial hair (e.g., beards, moustaches) that interferes with the seal against the worker’s face.

Implement engineering controls such as centralized dust collection systems.

  • Volatile Organic Compounds (VOCs)

Volatile Organic Compounds (VOCs)

What’s the risk?

VOCs, such as benzene, toluene, ethyl benzene, and xylene (often referred to as a group as BTEX), are emitted as vapors from crude oil.

Acute exposures to high levels of BTEX can cause:

  • Skin and sensory irritation
  • Central nervous system depression
  • Irritation of the respiratory system

Chronic exposure can negatively affect:

  • Kidneys
  • Liver
  • Blood-forming systems

Workers exposed to high levels of benzene in occupational settings may also have an increased occurrence of leukemia.

How are workers exposed?

VOC compounds tend to vaporize and become airborne easily. Vapor and mist may enter the body through ingestion, inhalation, and skin absorption.

High-exposure tasks include:

  • Preparing oil-based drilling mud
  • Sampling drilling fluid returned from the wellbore
  • Cleaning solids control equipment
  • Gauging storage and flowback tanks
  • Purging tanks, flow lines, and pipelines using xylene and toluene-containing solvents
  • Sampling mud that returns to ground level

How can you reduce risk?

At hydraulic fracture oil well sites producing natural gas, use “green completion” to capture the natural gas that escapes

Find and repair leaks, also known as “fugitive emissions,” which can occur at an oil well site.

Route emissions from pneumatic pumps to control devices.

Use automatic flowback sampling devices.

Eliminate visual mud tank inspection by substituting remote sensors.

  • Naturally Occurring Radioactive Material (NORM)

Naturally Occurring Radioactive Material (NORM)

What’s the risk?

This material, such as uranium, thorium, and radon, is present in oil and gas-bearing formations, including shale, granite, and sandstone. Employees inhaling NORM over several years could develop bone or other cancers from the exposure.

How are workers exposed?

Workers are exposed by inhaling or ingesting scale particles contaminated with radioactive material, such as radium-226. Radioactive material can become airborne when working with pipe and equipment containing radioactive scale. Workers may encounter this material in the following places:

  • scale build-up on internal pipe surfaces, downhole tubing, and flow lines
  • scale in produced water and brine storage tanks
  • sludge in tank bottoms, separators, dehydration vessels, and desalinators
  • crude oil pipeline scrapings
  • hydraulic fracturing process equipment

How can you reduce risk?

Workers should thoroughly wash their hands and face after working with contaminated equipment; before eating, drinking, or smoking; and at the end of the day.

Keep the number of personnel in the work area to a minimum.

If possible, seal or wrap all openings in contaminated equipment in plastic.

If repair or cleaning activities might produce dust or loose contamination, have employees wear a respirator appropriate for radioactive particulates.

Conduct repair or cleaning activities in well-ventilated areas, to which access has been restricted to help prevent loose contamination.

During cleanup, use plastic ground covers to contain contaminants.

Decontaminate gloves, respirators, coveralls, and cleaning towels, or properly dispose of them in sealed double bags.

Implement engineering controls such as centralized dust-collection systems to help prevent dust or loose contamination during cleanup.



What’s the risk?

The noise levels that oil and gas workers are exposed to on the job can result in hearing, impair work performance, and disrupt communication with co-workers and others. Overexposure to noise can also cause cardiovascular and other serious health problems.

How are workers exposed?

Virtually any oil and gas exploration and production operation produces noise that, without the proper safeguards and controls, can affect workers’ health.

Prime examples include prolonged exposure to noise caused by:

  • drills
  • generators
  • trucks
  • diesel and gas-powered engines
  • high-pressure pumping equipment

How can you reduce risk?

The key to preventing hearing loss is to remove the noise. When that’s not possible:

Provide and require the use of hearing protection by all employees working with or near generators, power tools, rock drills, heavy equipment, air compressors, trucks, and other noise sources.

Develop and enforce a hearing conservation program that includes noise assessments, engineering controls, audiometric monitoring of workers' hearing, appropriate use of hearing protection, worker education, recordkeeping, and program evaluation.

  • Diesel Exhaust

Diesel Exhaust

What’s the risk?

Diesel exhaust contains toxic air contaminants and is regarded as a human carcinogen by the World Health Organization.

Exposure to diesel exhaust can have both short-term and long-term health effects, including:

  • coughs
  • headaches
  • lightheadedness
  • nausea
  • further aggravation of chronic respiratory conditions (e.g. emphysema and asthma)

How are workers exposed?

Workers are normally exposed to diesel exhaust from vehicles present at work sites and diesel fuel-powered generators, pumps, welders, and other process equipment.

How can you reduce risk?

Pipe diesel exhaust away from work areas.

Perform routine maintenance on diesel engines.

Designate areas that are off-limits for vehicle traffic and engine operation.

Use cleaner-burning engines.

Use special fuels or fuel additives, such as biodiesel.

Install diesel-oxidation catalysts.