Some 350 million metric tons of asphalt are produced each year, mainly for road paving and roofing purposes. While asphalt has a variety of benefits, those who work with it can be subject to the health effects of occupational exposure to asphalt. For example, asphalt mishaps are responsible for incidents such as explosions and fires. Additionally, asphalt fume inhalation can also lead to short and long-term health issues.

These are all good reasons to ensure that if you're working with asphalt, you're wearing the proper personal protective equipment or PPE. The right PPE for asphalt work helps eliminate or reduce exposure to asphalt paving hazards. It's a big part of any job site safety plan, especially one where potentially hazardous materials are mixed and applied regularly.

This post takes a closer look at asphalt, explains what it is, where it's used, the hazards of working with it, asphalt safety and best practices, OSHA requirements for asphalt, and how to ensure asphalt worker safety.

What is Asphalt?

Asphalt is one of the most popular materials used in infrastructure and construction projects. Specifically, it is a black, viscous, oil-based liquid that often mixes with other solvents (diesel, naphtha, toluene, kerosene, etc.), binders, hardeners, and bonding agents until it hardens and creates a solid surface. Other materials such as crushed rock and recycled rubber are often added.

Industries that Regularly Use Asphalt

Asphalt is primarily used for infrastructure and construction purposes. In fact, it's estimated that road construction accounts for the majority of asphalt used, where it is mixed with other aggregates to create the asphalt concrete roads that Americans drive on every day.

Aside from infrastructure, asphalt is also used to create waterproofing products, roofing felt, and roofing materials, and it's used as a sealant for flat roofs.

Hazards of Working with Asphalt

There are a few hazards that are associated with asphalt which are covered below. However, it's critical to note that there are no Occupational Safety and Health Administration (OSHA) regulations for asphalt fumes.

  • Fire/explosion: There's a significant fire hazard associated with asphalt due to the high temperatures that it's stored and handled at, and because it's composed largely of crude oil. Because of these high temperatures, it could ignite — especially if it comes into contact with a spark, open flame, or another source of ignition.
  • Asphalt fumes exposure: Asphalt is typically heated between 150-200 degrees F to liquify it, allowing workers to pour and spread it. However, the process of heating asphalt releases harmful fumes. Hot asphalt can emit H2S (hydrogen sulfide gas) which can cause lung irritation, suffocation, or even death.
    The most common effects of inhalation include throat and eye irritation as well as nasal and lung irritation. This can cause a sore throat or cough. Inhalation can also lead to headaches, dizziness, and fatigue. Inhalation of certain asphalt mixes can lead to liver, kidney, and nervous system damage.
    Long-term asphalt fumes health effects include bronchitis, emphysema, and worse; asphalt inhalation has also been linked to some cancers.
  • Bodily exposure (skin burns and chemical absorption): Since asphalt is stored and handled at high temperatures, it's important to keep the substance off the skin. Failure to do so can lead to serious burns, rashes, and other skin defects. It can also potentially increase the risk of skin cancer.

Additionally, the eyes may also become irritated by asphalt fumes or from asphalt particulate. If asphalt were to come into contact with the eyes, workers should locate the on-site eyewash station and flush the eyes for at least 15 minutes.

Asphalt Worker PPE

The good news is, you can minimize or even eliminate any health risks by ensuring that workers are donning the appropriate PPE. Here's a look at what to wear to keep employees protected when working with this material:

  • Gloves: Gloves should be thermally insulated to ensure that no asphalt comes into contact with the skin and risks burning or irritating it. Solvents can soak into the skin if the proper gloves are not worn - cloth or leather gloves should be avoided.
  • Coveralls: Coveralls get their name because they "cover all." And this is important for ensuring that no asphalt makes skin contact anywhere on the body. If coveralls aren't on hand, make sure to wear a long sleeve shirt and pants to cover as much of the body as possible.
  • Face shield or safety glasses: Eye protection is essential when working with asphalt. Safety glasses do a nice job of protecting the eyes, but to ensure the entire face is protected, consider a full-face shield.
  • Respirator: Asphalt fumes and respiratory protection is critical. For increased safety, workers should wear a properly fit-tested respirator. A full-face mask respirator with vapor cartridges works best for applications with high vapor emissions.

Dust masks typically do not provide adequate protection, but a respirator will. It's especially important to have the right respiratory protection when working with asphalt in confined or enclosed areas.

However, asphalt safety precautions aren't complete solely by wearing the proper PPE. There are a variety of safety precautions you can and should be doing on-site to reduce risks. Below is a general asphalt paving safety checklist to consider:

  1. Know your job site: Any job site orientation should include a review of where to find certain emergency safety devices. For instance, employees must know where the fire extinguisher is located in the event of asphalt ignition. They should also know where the eyewash station is in the event it is needed. Make sure all workers go through a proper site safety orientation before they're permitted to work on the site.
  2. Understand the MSDS / SDS: The Material Safety Data Sheet, or MSDS, helps inform workers of the ingredients of a product as well as the potential health hazards associated with it.
    Why? First, asphalt is blended with a solvent in order for it to take on more of a liquid form. Second, the solvent(s) that it is blended with often range in toxicity. It's crucial to know what your asphalt mix has been "cut" with, so you know the potential health hazards. Some mixtures are more toxic than others.
  3. Engineering Controls: Mix the asphalt in an enclosed space. Try not to mix it in an open kettle. This potentially exposes workers to fumes and increases the risk of a fire. If asphalt is mixed in an open kettle, consider improving onsite ventilation or scheduling the process when fewer workers are on-site.
    Automating the process of open kettle mixing is another consideration. Mechanical devices can achieve this without exposing a worker to fume inhalation.
    Ensure warning signs are posted in the work area, the SDS is accessible, and that workers have been properly trained on the hazards of working with asphalt.
  4. Don't eat or drink anything around asphalt: Have a designated area well away from where asphalt is being mixed and applied so that anything workers consume is unlikely to be contaminated with asphalt or asphalt byproducts. It's also important to ensure that workers wash their hands properly prior to eating anything. Smoking should never be done around asphalt.
  5. Cut asphalt with more health-friendly aggregates: If possible, use asphalt products with a lower toxicity or that are safer to handle. For example, rapidly curing asphalts use solvents to help them cure faster. However, this increases both the risks of vapor emission and of fire. Asphalts used for lower temperature applications or a slower cure reduce the risks of fumes and fires.

Additionally, workers need to be aware of the signs and symptoms of asphalt inhalation or exposure so they can seek proper treatment before more severe problems develop.