Researchers analyzed over 48,000 metalworking fluid samples from machines worldwide over 10 years and found that fungal contamination is very common, especially on machine surfaces. While companies add chemicals called fungicides to prevent fungal growth, these chemicals have limited effectiveness and fungi often survive or adapt to them. As regulations increasingly restrict these fungicides, the manufacturing industry will need to find new ways to prevent fungal contamination by changing the chemical composition of metalworking fluids themselves.