VIDEO: Wenham Crew Assists After Middleton Plant Explosion

Middleton public safety officials are saying there is no reason for concern

Air quality tests have been performed and there is no issue. However, they are also asking nearby residents to stay indoors and keep doors and windows closed.

Health officials are monitoring the nearby Ipswich River to see if any chemicals were released into the riverway, said Middleton Fire Chief Frank Twiss.

The Ipswich River flows easterly towards Hamilton and Wenham from the plant, helping form the Wenham Swamp and then making the Hamilton town line to the north with Ipswich.

The cause of the explosion is under investigation. It is uncertain what chemicals were involved, said Twiss.

Crews from at least nine North Shore fire departments assisted in Middleton, including an engine from the .

Middleton firefighters responded to a scene at 7:39 p.m. after reports of an explosion. People all over the North Shore reported hearing the explosion and some likened it to hearing the Danversport explosion in 2006. Residents in Hamilton and Wenham reported feeling in the Danversport explosion as well as Sunday night's explosion in Middleton.

Firefighters found a “heavy volume of fire” when they arrived. Ultimately, firefighters stuck four alarms to bring more area firefighters to the scene.  Lynnfield, Peabody, Salem, Beverly, North Reading and North Andover apparatus are just some of the other firefighters who responded to the scene.

The fire was knocked down in 40-50 minutes.

Four people were injured in the explosion and were taken to where a decontamination staging area was set up. No injuries are life threatening, said Twiss.

A tier 3 hazmat response was initiated, which is between 30 and 45 technicians. They checked the scene Sunday night.

There were no evacuations of area homes and no structural damage to those homes reported, according to Twiss.

Even so, Middleton Police Chief James DiGianvittorio is asking people to stay indoors and keep their windows and doors shut.

Coincidentally, Middleton firefighters held hazmat training at the plant in May, according to Twiss.

According to its Web site, Bostik is "one of the largest adhesive and sealant companies in the world. The group designs, manufactures and markets adhesives and sealants for three key markets: Industry, Construction and Consumer. Its products are used in a wide range of fields – from gas tankers and buildings to furniture and diapers."