But promising change and implementing it are two different things, and one year later, some UPS employees say that ratifying the contract has not improved their working conditions in summer temperatures. Many workers who spoke to Mother Jones described feeling pressure to keep up the pace and take fewer breaks, even in extreme heat.

While the company has made good progress on installing more fans, heat shields, and induction systems in trucks, air conditioning appears to be the most intractable change. Teamsters spokesperson Kara Deniz says the company’s lag in refurbishing trucks with air conditioning is “unacceptable.”