Abstract: At 10:30 a.m. on October 21, 2021, an employee was working as a machine operator at a machine shop. He was operating a Wohler metal strip brush (MSB) machine. It was known at the site as metal strip brush machine #11. This machine assembled filaments used for broom heads. He was working near an unguarded chain and sprocket. The unguarded sprocket was located where the filaments were loaded into the machine and then moved down onto a conveyor taking them to the assembly section of the machine. The conveyor was driven by a slow-moving chain and sprocket at waist height. The employees typically had no reason to reach in near the sprockets, but they did occasionally reach in near them to clean filaments which had fallen off the conveyor. In this incident, the operator reached in to check the tension of the chain. His thumb was caught in the in-going nip point of the chain and sprocket. He suffered a partial amputation, in that the tip of his thumb was amputated. He was hospitalized. Nine months earlier, another employee suffered a fingertip avulsion in a similar circumstance. That employee was checking the tension of a chain, when his finger was caught in the sprocket. He suffered a fingertip avulsion. The employer immediately installed a guard over the sprocket on that machine and stated that he was looking at all the other machines to do the same. In the nine months since that incident, the employer had not installed any guards on the similar machines. The employer started a safety committee after the first incident, and still the chain and sprockets on the similar machines were not guarded.