Photos: Black Lives Matter protesters charged for I-93 protest

Dozens of protesters were arraigned Thursday on charges of trespassing, disorderly conduct and resisting arrest, after they blocked traffic on Interstate 93 in Medford and Milton, snarling the morning commute and causing what police called a “serious risk to public safety.”

State Police arrested 29 supporters of the Boston chapter of Black Lives Matter, a national organization the protests violence against minorities.

At around 7:30 a.m., activists started unloading 55-gallon barrels, each filled with 1,200 pounds of concrete, from a rented box truck and spread them across the highway in Milton, according to Timothy P. Alben, Superintendent of the Massachusetts State Police.

Black Lives Matter organizers said the protest was meant to “disrupt business as usual” and confront white complacency in the systemic oppression of Black people in Boston.

In Medford, 17 people tied themselves together in what Alben referred to as “sleeping dragons,” chains of people tied to an expense of PVC pipe extending across the highway. In Milton, six people were tied to the barrels, requiring police to cut them free.

Activists who acted as lookouts and drivers were also arrested, Alben said.

Some of the protesters wore adult diapers in anticipation of a day-long demonstration, according to police, though the scenes were cleared by 10 a.m.

“This is not only immature and irresponsible, but the conduct is reckless and it endangers people’s lives,” Alben said at a midday press conference.

The protesters prevented an ambulance carrying an Easton crash victim with life-threatening injuries from reaching a level one trauma center in Boston, and forced it to divert to a smaller hospital in Brockton.

“Numerous other ambulances had to be on-scene while we cut protesters out of restraints, meaning they were not available if needed elsewhere,” said State Police Superintendent Timothy P. Alben. “Anytime you divert public safety services to an incident like this it creates other potentially catastrophic problems.”

A Black Lives Matter spokeswoman could not be reached following the afternoon arraignments, however shortly after the demonstration was underway organizers released a statement on Facebook.

“Today, our nonviolent direct action is meant to expose the reality that Boston is a city where white commuters and students use the city and leave, while Black and Brown communities are targeted by police, exploited, and displaced,” Korean-American activist Katie Seitz said in the statement.

Organizers named 20 people of color who were killed by law enforcement officers in Boston within the past 15 years, and said they “mourn and honor all these lives.”

Violent protests broke out across the nation late last year after grand juries in New York and Missouri declined to bring criminal charges against white police officers in the killing of unarmed black men.

“We must remember, Ferguson is not a faraway Southern city,” protester Nguyen Thi Minh Thu said in the statement. “Black men, women, and gender-nonconforming people face disproportionately higher risk of profiling, unjust incarceration, and death. Police violence is everywhere in the United States.”