The Fourth Avenue bridge over Bull Creek in Tarentum is closed after a sinkhole formed near the span.
Borough engineers said a storm sewer line beneath the road collapsed, causing ground instability.
It poses a risk to the bridge and surrounding infrastructure, according to an online post by the borough.
“Due to the seriousness of the situation, and upon the recommendation of our engineer and solicitor, Tarentum has declared a local emergency to ensure we can respond quickly and effectively,” the post said.
Access to businesses remains open by way of Center Street.
There was no timeline available for the road’s reopening.
