FRESNO, Calif. (KSEE/KGPE) – An IRS building in Fresno has been partially evacuated after what Fresno Fire described as an "unknown substance" was found inside Tuesday morning. Fresno Fire HAZMAT crews responded to the building in southwest Fresno at around 8 a.m. The building is near Northpoint Drive and Fortune Avenue. Several people were evacuated and no injuries were reported. According to the Fresno Fire Department, the building at 3211 S. Northpoint Drive is a large facility and it is unknown how many people were evacuated from the site. "A portion of the building is still operating, just where the package is at that portion has been evacuated," said the Fresno Fire Department's Josh Sellers. Fresno Fire's HAZMAT team will be making entry to the building to get a sample of the substance to determine what it is, Sellers says. It is unknown how long the Fresno Fire Department and other officials will be at the IRS facility. No other information was provided by the Fresno Fire Department. This is a developing story.