Hanover, Massachusetts, zip code 02339, currently operates under a critical environmental hazard designation. The region contains 26 environmentally compromised locations within a ten mile radius, including five active sites within five miles. The primary regulatory focus is Electro Signal Labs, an active site on the National Priorities List located 3.7 miles from the Hanover center. Additional significant nearby facilities include National Fireworks, Rockland Warehouse Fire, Fabricare House, and the South Weymouth Naval Air Station.

The Environmental Protection Agency identifies the primary threats originating from Electro Signal Labs as unspecified hazardous substances. While exact chemical profiles remain broadly classified under this regulatory umbrella, exposure to such industrial byproducts typically occurs through groundwater migration or vapor intrusion. Sustained exposure to these types of volatile and semivolatile compounds can affect residents by disrupting endocrine function, impairing neurological development, and increasing specific carcinogenic risks. Because Electro Signal Labs retains an active National Priorities List status, the location remains in the ongoing remediation and monitoring phase, meaning federal cleanup objectives are established but not yet fully achieved.

Given the high concentration of active environmental sites in this specific zip code, residents must implement immediate household safeguards. Households utilizing private domestic wells should test their water supply biannually for volatile organic compounds and heavy metals. Furthermore, residents should install certified reverse osmosis water filtration systems to mitigate potential municipal or private groundwater contamination risks. Property owners should also conduct indoor air quality assessments to detect potential soil vapor intrusion originating from the nearby subterranean chemical plumes.