Transit officials have come up with new safety measures as the result of a controlled blast last month that sent rocks flying into streets on the Upper East Side.
The Metropolitan Transportation Authority says a superintendent will now have to sign off on a pre-blast checklist.
A second licensed blaster will verify that proper preparations have been made.
A double layer of protective mats will be used when blasting in shafts.
Construction workers were blasting on Aug. 21 to create an escalator for the planned Second Avenue subway line at East 72nd street and 2nd Avenue. The blast lifted two 1,800-pound steel plates and allowed debris to rain down onto the streets.
Blasting will resume Friday in the station cavern. It will resume next week at the ancillary shaft where the incident occurred.