By Sue Ellen Woodcock
Recently a truck traveling to the MWRA site on Deer Island drew the ire of residents when observers noted the chemical sign number on the truck for one chemical, but officials have stated that it was another chemical being transported.
According to Ria Convey, spokesperson for the MWRA, said the truck headed for Deer Island at 8 a.m. on April 7 was carrying sodium bisulfite and not isobutyl methacrylate. This chemical is used to de-chlorinate the final effluent before it’s discharged through the outfall tunnel to Massachusetts Bay.
“The number identified by the resident, 3671, does not match anything that has ever been delivered to Deer Island,†Convey said in an email, adding that the MWRA receives this chemical at the plant about 26 times a year.
Sodium bisulfite is non-explosive and non-toxic. It has a mild sulfur odor, according to the information sheet about the chemical.
 “No police escort is required for routine chemical deliveries – only for large fuel oil deliveries,†Convey explained.
Convey added that all chemical delivery trucks comply with federal and local department of transportation (DOT) standards. The trucks must be properly labeled during transportation, carry bill of ladings, must carry proper safety and spill containment equipment on the truck, and must be driven by experienced and properly licensed commercial drivers.
The trucks are required to be inspected on a regular basis according to DOT standards and maintain all records for audit by the MWRA should it choose to audit them but more importantly for auditing by DOT. MWRA staff review the receipt of delivery and take a sample of the chemical to confirm before offloading.
Convey said the MWRA requires all chemical trucks to follow very specific delivery protocol – chemical shipments must travel on the Deer Island Truck Route once inside Winthrop, must obey all posted speed limits, must arrive and be offloaded only during the business day, Monday through Friday, from 7 a.m. to 3 p.m.