Classes ended early Thursday at Brookline High School, where officials said they were responding to a hazardous materials situation.In a statement, the district said staff was alerted to a "chemical irritant" that was found near a first-floor bathroom, close to the cafeteria, in the 115 Greenough Street building. All students and staff were evacuated at approximately 11:47 a.m. Sky5 flew over the campus shortly after 1 p.m. and saw large numbers of students outside, along with ambulances and Brookline Fire Department vehicles.At least two students and two staff members were taken to the hospital for evaluation and treatment, the district said. The Brookline Police Department confirmed the response was due to a hazmat situation and that school will remain closed for the rest of the day. After everything was ventilated and deemed safe, students were allowed back into the building to collect their belongings. Parents were told to pick up their students on Lowell Road or Greenough Street, police said. All other traffic was asked to avoid the area. "It's strange," said student Jerry Yang. "It's never happened before but the school administration did a great job getting us out safely and orderly."