MIDDLESEX TWP — The ninth session of the zoning hearing board regarding the challenge to a zoning amendment approved in August by supervisors will be held later than originally announced.

Township manager Eric Kaunert said the hearing time has been moved from 4:30 to 6:30 p.m. on Tuesday.

The hearing is the result of a challenge to a gas and oil amendment to the township zoning ordinance passed in August by the supervisors.

Four Middlesex residents plus the Philadelphia-based environmental groups the Clean Air Council and the Delaware Riverkeeper Network are challenging the zoning amendment saying it allows unconventional gas drilling operations in much of the township.

Attorneys from the township, Rex Energy and MarkWest Energy Partners support the amendment.

The challenge caused a halt to the work on the five Rex Energy gas wells at the Bob and Kim Geyer farm on Denny Road, which a group of Mars School District parents have protested because they say shale gas drilling operations would pose a health and safety hazard to the students in the nearby Mars schools.

The hearing has been attended by hundreds of people since it began in November.

Mike Gallagher, the zoning hearing board solicitor, said the board would likely rule on the amendment in late April.