Bjs wholesale club work in an unsafe environment hudson Massachusetts

I worked for Bjs in Hudson, Ma.  I was in the tire bay for the last 4 months. For more than 50% of my shifts I worked alone with no one around to see if I had been hurt or in need of a break.  Some of these shifts were for up to 11 hour shifts.  At no time during these solo shifts was I allowed a break or offered relief by someone in the store.  No lunch breaks or 15 minute breaks.  When I questioned Mike the operations manager he stated that they were trying their best to hire someone.  When I told him that if I was injured while working alone the time it might take someone to find me could be a big difference in getting immediate care, he told me that this was what i was going to have to deal with if I wanted to continue working at Bjs.  I took this as a threat to my job security.