The history of sandblasting reveals that workers are sometimes exposed to health hazards for decades before government entities craft or update safety regulations. The evolution of sandblasting into modern-day materials highlights why frontline workers need to wear media blasting safety equipment.
Commonly known as sandblasting before the 1990s, the process of spraying sand (silica) at objects for cleaning and shaping them caused widespread health conditions. Now this practice is called “abrasive media blasting” and due to the evolving materials used, organizations such as the Environmental Protection Agency (EPA) and Occupational Safety and Health Administration (OSHA) were forced to carve out stringent regulations to protect workers.
A closer look at the history of media blasting safety, the changing materials, and the impact they have on working people show more needs to be done in terms of requiring personal protective clothing and media blasting safety equipment.
When was Abrasive Blasting Developed?
American Civil War officer Benjamin Chew Tilghman filed a patent for the sandblasting process in 1870. During his service in the 26th Pennsylvania Infantry Regiment and 29th Pennsylvania Volunteer Infantry, he reportedly witnessed the effect of wind-blown sand on windows in the desert. This experience became the basis for developing the commercial process.
A year after patenting sandblasting, he received the Great Medal of Honor from the 40th Exhibition of the American Institute of the City of New York. By 1877, he began evolving the blasting process, filing a more refined patent called “Liquid Grindstone.”
In 1904, Thomas Pangborn built on the sandblasting process by using compressed air to propel the tiny bits of silica sand. This led to more prevalent use in industries such as construction and refinishing. The U.S. Navy concluded that sandblasting was a necessity when repainting vessels. The military defense wing determined that unless old paint was sandblasted off, new coats would not properly adhere to ship hulls.
But during the early 1990s, the cheap Crystalline and Amorphous Silica used in sandblasting was linked to lung cancer and other serious health conditions. In 1997, the International Agency for Research on Cancer formally recognized crystalline silica as a human carcinogen. These watershed events triggered changes in the types of material used but did not sufficiently heighten media blasting safety practices such as enforcing the use of personal protective equipment.
What Industries Commonly Use Abrasive Blasting?
Like the U.S. Navy, wide-reaching industries found abrasive media blasting to be among the most cost-effective and efficient methods to remove coating and surface growths, among others. The most common industries using abrasive media blasting today include the following.
- Shipbuilding and Hull Cleaning
- Automotive Restoration
- Metal Refinishing
- Metal Casting
- Surface Coating
- Surface Cleaning and Preparation
- Glass Etching and Engraving
Rather than go back to labor-intensive scraping and machine sanding, abrasive blasting operations pivoted to materials not yet deemed a health hazard by the EPA or requiring expensive media blasting safety equipment by OSHA. That also evolved following the OSHA Respirable Crystalline Silica regulation.
What is the OSHA Respirable Crystalline Silica Rule?
To say media blasting safety measures and PPE requirements were slow in coming would be an understatement. Inhaling silica dust has historically been associated with “miner’s lung.
Dr. Bernardino Ramazzini, widely considered the founder of occupational medicine, found evidence silica impacted the health of stone cutters during the 1600s. U.S. Labor Secretary Perkins established a National Silicosis Conference and initiated a “Stop Silicosis” campaign in 1938. And long-standing Secretary of Labor Robert Reich orchestrated the “It’s Not Just Dust” awareness program in 1996 that pushed for regulatory media blasting safety guidelines.
Although researchers declared crystalline silica a human carcinogen on multiple fronts, OSHA didn’t publish its final Respirable Crystalline Silica rule until 2016. Focused broadly on the estimated 2 million at-risk construction workers at 600,000 job sites, the rule limits exposure.
The regulation sets the 8-hour permissible exposure limit (PEL) at 25 micrograms of silica per cubic meter of air. When people in the environment are exposed to 25 PEL or higher over 8 hours, companies are required to provide abrasive blasting PPE such as respirators and disposable masks. No employee may be exposed to 50 PEL over 8 hours.
Are OSHA Media Blasting Safety Regulations Already Outdated?
The slow rulemaking pace of federal organizations poses a safety risk for workers. For example, the first asbestos regulations weren’t promulgated until 1971. Those safety regulations and PPE requirements have been updated several times during the last 50-plus years. That being said, other workplace materials are equally, if not more, dangerous than the airborne crystalline silica found in sandblasting.
One such material is beryllium-copper, a strong, non-corrosive metal widely used in the aerospace, energy, telecommunications, medical, and defense sectors. Beryllium oxide is commonly used in ceramics and electrical equipment. Beryllium is also found in the fly ash and slag of coal-fired plants and foundries.
Workers who inhale airborne particles of beryllium are at risk of contracting chronic beryllium disease (CBD), a lung condition. Approximately 62,000 workers are exposed to beryllium materials annually. It’s also important to note that dermal contact with beryllium dust presents a clear danger to workers.
The material can enter the bloodstream through minor cuts and abrasions. It is also easily transferred from the hands to the face, where it is inhaled into the lungs. The media blasting safety equipment deployed in these environments must be comprehensive and include disposable protective clothing to cover the entire body, as well as breathable masks.
The OSHA guidelines previously allowed a beryllium PEL of 2 micrograms over 8 hours. The new rule lowers that exposure to 0.2. That constitutes a drastic departure from what was once believed to be safe levels of airborne dust. The stringent changes regarding beryllium raise questions about media blasting safety, particularly how new materials affect worker health and safety.
Alternative Abrasive Blasting Materials
The heightened regulations and health conditions surrounding materials such as crystalline silica prompted industries to pivot to alternatives. People who enter occupations that require media blasting processes are not necessarily equally at risk.
While the initial concept was to project sand at a high velocity, modern applications take other factors into consideration. These include the hardness, shape, friability, and density of the material. The conventional thinking around abrasive material selections involves the quality result of the blasted item. Hard materials such as aluminum oxide can aggressively remove caked-on materials. When hard abrasives also have jagged edges, they are particularly effective at removing items such as the paint from a ship’s hull.
Friability typically refers to how the abrasive stands up to impact. Softer materials can splinter, making them less effective on rugged surfaces. However, this makes softer materials a better choice for delicate applications such as glass cleaning. Density simply refers to the weight of a media. These rank among the common sandblasting alternatives in use today.
- Baking Soda: Also known as “Soda Blasting,” the material is used to clear away paint and grease. It is considered environmentally sustainable but poses a health risk if inhaled.
- Dry Ice: The primary advantage of using dry ice is that it minimizes surface scratches. However, pressurized carbon dioxide poses a substantial danger to human health.
- Walnut Shell and Corn Cob Meal: These materials are frequently used to remove rust. Ranked among the healthier options, workers are advised to wear abrasive blasting PPE.
- Crushed Glass: Also considered safer than silica, glass materials may still cause long-term health issues.
- Calcined Aluminum Oxide: Exposure may result in irritation to the nose, throat, and lungs.
- Garnet: Although not necessarily toxic, inhalation can result in lung conditions.
Abrasives such as synthetic olivine are being crafted with an eye toward worker safety. Regardless of a material’s non-toxicity, breathing in dust has a negative impact on the respiratory system.
Need for Abrasive Blasting PPE Remains Unchanged
The history of sandblasting demonstrates that safety regulations often trail behind proven health dangers. The current regulation for beryllium exposure indicates ongoing research continues to identify new health conditions that prompt OSHA and others to eventually create more stringent safety rules.
Depending on the application, workers engaged in abrasive media blasting are required to wear breathable masks or a respirator, and disposable protective clothing. International Enviroguard produces and distributes a complete line of disposable protective clothing and accessories for blasting operations.