The U.S. Postal Service has determined that a barometer sent in the mail was the source of a mercury leak in a postal vehicle last month.
Overall, the mercury leak affected 71 packages, but only 24 are safe for delivery, USPS spokeswoman Freda Sauter said.
The spill happened Aug. 30 in the 4600 block of Noland Boulevard. The scene was active for several hours while Virginia Department of Emergency Management officials worked to determine what the substance was.
Sauter said the barometer contained a “substantial amount of mercury” and was sent in violation of postal regulations.
Following the spill, the postal service brought in an outside environmental contractor to collect and conduct tests on the packages. Those tests were finalized last week, Sauter said.
Fifty-seven of the packages cannot be delivered, the contractor found.
The postal service will send letters explaining the situation to residents whose packages were affected.
“We apologize for any inconvenience to our customers,” Sauter said in an email Wednesday.
Postal Inspector Michael Romano, of the United States Postal Inspection Service’s office in Richmond, said the incident is still under investigation.
Postal inspectors have identified the barometer’s sender and have been in contact with them, Romano said.
Postal inspectors evaluate each incident on a case-by-case basis to determine whether it is a criminal matter or requires a civil fine, Romano said.
If the case is criminal, it will be sent to the U.S. Attorney’s Office for possible prosecution, Romano said. If it is civil, it will be sent to the Postal Inspection Service’s headquarters where officials evaluate whether the mailability standards have been violated.
In the mailability standards, section 348.21 specifically addresses mercury, stating the substance cannot be sent unless it is under a certain amount and clearly marked.
Note: This story has been updated to include information from the United States Postal Inspection Service.