Tungsten carbide high velocity oxygen fuel has been recognized as a viable replacement for hard chrome electroplating. Tungsten carbide provides hardness that surpasses that of hard chrome electroplating with minimal and controlled environmental and health  impact. High Velocity Oxy-Fuel (HVOF) is a subset of flame spray that is commonly used to produce highly wear-resistant coatings such as tungsten carbide. It uses an internal combustion chamber and a diverging/converging nozzle to heat and accelerate the powdered coating material. The kinetic energy produced by the extreme velocities helps produce coatings that are very dense and very well adhered.
Environmental Health and Safety Issues and Risks
Thermal sprays such as HVOF are generally safe to both the environment and workers because of their insolubility in water and the controlled nature of the process. Simple and inexpensive precautionary procedures can easily be taken. However, there are still risks especially when handling the equipment, thermal spray powder and the sprayed parts. The primary health risk issues are associated with direct skin contact and inhalation of the tungsten carbide powder. To avoid these risks, make sure the powder is handled in a controlled manner, that the HVOF jet exhaust is released in a contained, controlled and localized booth where access is limited to workers and a ventilation exhaust system is installed in every thermal booth to remove any gaseous tungsten-carbide that may escape the local spray area.
Possible Health Risks
After a comprehensive study conducted by the National Institute for Occupational Safety and Health (NIOSH), the following health problems were noted to a significant, yet still relatively small percentage of workers: upper respiratory tract irritation, exertional dyspnea (shortness of breath), coughing, weight loss, allergic reactions, lung congestion, changes in blood pressure, sleep disturbances, dizziness, nausea and vomiting. All of these symptoms are attributed to tungsten carbide exposure. However, these symptoms eventually subsided within a year after the worker was removed from the working environment.
Precautionary Measures
The same study provided a system of recommendations to protect workers against environmental health risks posed by tungsten-carbide-based materials. The workplace should set requirements for insoluble, soluble and cemented tungsten carbide-based work areas. A pre-health evaluation should be done for every worker. Moreover, respiratory education and evaluation must be performed as well as treatment and education of exposed workers. Health warnings, locations and requirements of work areas and containers must be labeled and clearly posted. Personal protective equipment must be issued to workers. Sanitation requirements like hand washing, dining requirements, hazardous and toxic waste disposal rules must be implemented.