trademark and trade secret laws, non-disclosure agreements and other intellectual property protection methods to protect our proprietary technology. We believe that, due to the rapid pace of technological innovation in the markets for our products, our ability to establish and maintain a position of technology leadership depends as much on the skills of our research and development personnel as upon the legal protections afforded our existing technologies. To protect our trade secrets, we take certain measures to ensure their secrecy, such as executing non-disclosure agreements with our employees, customers and suppliers. However, reliance on trade secrets is only an effective business practice insofar as trade secrets remain undisclosed and a proprietary product or process is not reverse engineered or independently developed.
In addition to proprietary process trade secrets, we also file patents. To date, we have been issued 111 patents that relate to our VGF products and processes; 83 in China, 11 in the United States, 8 in Japan, 4 in Taiwan, 3 in the European Union, and 2 in Germany. Patents have a protected life of 20 years (or 10 years for utility model patents in China) from their filing dates. Our patents have expiration dates ranging from 2023 to 2038. In some cases we may consider filing divisional, continuation or continuation-in-part of the existing patents for additional claims. We have several patent applications pending in China, United States, and rest of the world. Furthermore, in aggregate, our consolidated raw material companies have been issued 59 patents in China, including 26 patents issued to JinMei and 59 patents issued to BoYu.
In the normal course of business, we periodically receive and make inquiries regarding possible patent infringement. In dealing with such inquiries, it may become necessary or useful for us to obtain or grant licenses or other rights. However, there can be no assurance that such licenses or rights will be available to us on commercially reasonable terms. If we are not able to resolve or settle claims, obtain necessary licenses on commercially reasonable terms and/or successfully prosecute or defend our position, our business, financial condition and results of operations could be materially and adversely affected.
Environmental Regulations
We are subject to federal, state and local environmental and safety laws and regulations in all of our operating locations, including laws and regulations of China, such as laws and regulations related to the development, manufacture and use of our products, the use of hazardous materials, the operation of our facilities, and the use of the real property. These laws and regulations govern the use, storage, discharge and disposal of hazardous materials during manufacturing, research and development and sales demonstrations. We maintain a number of environmental, health and safety programs that are primarily preventive in nature. As part of these programs, we regularly monitor ongoing compliance. If we fail to comply with applicable regulations, we could be subject to substantial liability for clean-up efforts, personal injury, fines or suspension or be forced to cease our operations, and/or suspend or terminate the development, manufacture or use of certain of our products, the use of our facilities, or the use of our real property, each of which could have a material adverse effect on our business, financial condition and results of operations. The regulatory landscape shifts and changes in China as that country works to improve the environment. Because we manufacture all of our products in China, we are subject to an evolving set of regulations that could require changes in our equipment and processes and require us to obtain new permits. In 2017, China increased its focus on environmental concerns which increased pressure on manufacturing companies. During periods of severe air pollution in Beijing, manufacturing companies, including AXT, may be ordered by the local government to stop production for several days. For example, in the first quarter of 2018, over 300 manufacturing companies, including AXT, were intermittently shut down by the local government for a total of ten days from February 27 to March 31, due to severe air pollution.
Human Capital
As of December 31, 2022, AXT and Tongmei had 1,076 employees, which consisted of 26 employees in our headquarters in Fremont, California, one sales professional in France and 1,049 employees in our factories in China. In addition, our consolidated raw material companies had, in total, 483 employees. In aggregate, we and our consolidated raw material companies had 1,559 employees, of whom 1,158 were principally engaged in manufacturing, 184 in sales and administration and 217 in research and development. Of these 1,559 employees, 26, consisting of sales and marketing, accounting and finance, administration and corporate executives were located in the United States, one in