BOSTON (CBS) – A suicide led to a dangerous situation at an apartment on Massachusetts Avenue overnight.

WBZ NewsRadio 1030′s Karen Twomey reports

Firefighters and police were called to 676 Mass. Ave. after a 25-year-old woman ingested a deadly chemical around 9 p.m. Monday.

As a precaution, authorities evacuated the four-story apartment building and two neighboring brownstones.

Investigators leave 676 Mass. Ave. in hazardous materials suits overnight.

They also shut down Mass. Ave. between Washington and Harrison Avenues.

The woman, who was a grad student and Ph.D candidate in pharmacology at Boston University, was taken to Boston Medical Center, where she died.

BU officials said there was no sign that any chemicals were taken from the school.

“This is a very sad day for our community. Our thoughts are with the family during this very difficult time,” the school said, in a statement.

Four police officers and two EMTs were also taken to the hospital as a precaution to see if they were affected by the substance, which is said to be sodium azide, a chemical used in airbags for cars.

When it metabolizes it becomes almost like cyanide and it can be a highly lethal compound.

Dep. Chief Steve Dunbar said the woman died only a few hours after she ingested the material.

Her name has not been released.

One of her relatives said she told her that she had swallowed the chemical and had requested that somebody take care of her cats.