Recently, I came across a safety report: On August 1, 2004, at approximately 8:00 AM, Mr. Yu, a weigher at a tire manufacturing plant in the western suburbs of Shanghai, was cutting small pieces of rubber in the rubber mixing workshop. To save time, he violated safety operating procedures by using a key to hold down the right button of the two-hand safety device, leaving it in a semi-operational state. When he pressed the button with his left hand, his right hand was on the rubber material, resulting in the severed section of his index finger and two sections of his middle finger being cut by the rubber cutter blade, constituting a serious injury. The direct cause of the accident was Mr. Yu's violation of operating procedures. He violated the company's safety operating procedures for the rubber cutter by using a key (instead of one hand) to hold down the right button of the two-hand safety device, leaving it in a semi-operational state, ultimately leading to the accident. An indirect cause was inadequate management. The workshop and team management personnel did not provide sufficient and detailed job safety education and training for employees. When employees were found to be violating regulations, they failed to take effective preventative measures and were not strict enough in enforcing safety production management systems. Accident responsibility: Yu violated the company's safety operating procedure that "single-blade rubber cutters must be operated with both hands only" when operating the rubber cutting machine. Even after being pointed out and asked to correct his violation, he continued to act as he pleased, leading to the accident. He should bear the primary responsibility for this accident. The workshop production management personnel also bore partial responsibility for the accident due to inadequate education and training and insufficient enforcement of safety management systems. As a machine safety engineer, I believe there are shortcomings in the company's accident analysis and responsibility determination. It only saw the surface phenomena and failed to identify the fundamental technical "blind spot" that caused the accident. I also question the claim that "if one button is pressed, the two-hand button protection device is always in a semi-operational state." Since it's a two-hand button safety device, the cutting machine should only cut the glue when both buttons are pressed simultaneously. If one button is pressed first, then the other, the cutter should not cut the glue. According to EN574, the standard for two-hand devices, regarding their application in hazardous machinery, in dangerous situations, especially in manually fed machines, stamping equipment, and machines with cutting blades, the device is only effective when both buttons are pressed simultaneously with a time difference of at least 0.5 seconds. Furthermore, if the time difference exceeds 0.5 seconds, both hands must be released before the device can be used again. Only in this way can the operator's hands be kept away from the danger zone and protected from injury. Only two-hand devices that meet the standard requirements can be sold on the market. Clearly, the fact that the two-hand control device of this equipment does not meet the standard's safety requirements is the root cause of the serious accident that severed the operator's fingers. Therefore, as a safety device, the two-hand button must be paired with a safety monitoring module (also known as a safety relay) to form a safe two-hand control system. Its working principle is as follows: The two normally open and two normally closed signal contacts of the two-hand buttons are connected to the safety monitoring module, which judges the status of the two-hand buttons. The safety monitoring module will only output when both buttons are pressed simultaneously within 0.5 seconds, and only then can the system start the machine. Faults in any contact can be monitored and judged. When either hand leaves the button, the safety device immediately stops the output and cuts off the power source, thereby achieving the purpose of protecting the operator. Premature or delayed operation of either button will not cause danger. However, some companies, in an attempt to save money, do not purchase or install the safety monitoring module in their two-hand control systems. They simply connect the two normally open contacts of the two buttons on the button box in series to the machine control circuit. While it appears to be two-hand control, it is actually just two buttons connected in series. This can easily be "short-circuited" by the operator, turning it into one-handed operation. Furthermore, a welding failure in one contact can also easily make one-handed operation possible; if two contacts fail, it may even cause unexpected equipment operation and injure the operator. Therefore, connecting two buttons in series is unsafe and cannot achieve the safety function of a two-button device. Doing so is not allowed and is extremely dangerous. Two buttons do not constitute a two-button system. The statement that "pressing one button keeps the two-button protection device in a semi-operational state" is a misunderstanding of two-button devices and reflects a misconception. This "semi-operational state" misleads others into believing that one button can achieve half-operation, which is incorrect for two-button devices. It can be said that this serious injury accident was entirely avoidable. If the company's equipment had met safety requirements and had a safety monitoring module installed, even with the worker's violation of regulations, three finger joints would not have been lost. However, the accident has already occurred, and the consequences are irreversible. Here, I not only feel regret and sympathy for Mr. Yu, but also feel ashamed of the company's safety precautions. In light of this painful lesson, besides the person involved regretting not following the prescribed operating procedures, shouldn't the manufacturing company reflect on whether, given the blind spots and ineffectiveness of strengthened management and education measures, they should consider: Are our machines safe in terms of equipment safety hardware? Is it necessary to upgrade existing equipment to improve safety and reliability? Should they purchase and use safety products and machinery in the future? If every enterprise and institution can ensure the safety of its environment, production equipment, and machinery from a technical and hardware perspective, and supplement this with traditional ideological education, safety training, and strengthened institutional management, creating a more comfortable and safer working environment for employees, it will benefit the enterprise, the employees, and society as a whole. We also hope that this publication will clarify this erroneous statement and play a role in helping the company improve its equipment safety.