A fast-moving blaze broke out Sunday afternoon at a mulch company in Peabody, spreading thick, black smoke around the neighborhood.
Because of the thick smoke, State Police closed part of exit 45 connecting Interstate 95 north to Route 128 south Sunday afternoon, causing traffic backups.
The fire at J.D. Raymond Transportation on Farm Avenue destroyed at least two large construction vehicles — including a tanker truck, said Peabody Fire Chief Steven Pasdon.
Pasdon was unable to say what sparked the blaze, and he estimated damage at more than $1 million.
Investigators will probably likely need to spend several days on site ensuring that no lingering embers remain buried in the tons of mulch and wood chip piles at the scene, Pasdon said.
Cathy Hartigan said she was headed back to her home on Farm Avenue near the mulch plant at about 5 p.m. Sunday when she saw the smoke, briefly mistaking it for a storm cloud.
Other witnesses reported hearing explosions as the fire consumed the mulch yard, Pasdon said.
Hartigan was able to return to her home but said that police were keeping onlookers away from the site. She said she and her neighbors were concerned about the potential health effects of the blaze, because the mulch yard is close to an old landfill.
Matthew J. Lee of the Globe staff contributed to this report. Emma Stickgold can be reached at email@example.com.