After initially rejecting requests from the National Highway Traffic Safety Administration to recall 2.7 million sport-utility vehicles, auto manufacturer Chrysler has agreed to recall 1.6 million vehicles over alleged safety problems concerning gas tanks.

Jeep Liberty vehicles made from 2002 to 2007 and Jeep Grand Cherokees produced between 1993 and 1998 will be recalled by the manufacturer because of alleged problems with the vehicles’ gas tanks. Authorities said the tanks’ location behind the rear axle, near their rear bumpers, made them more vulnerable in the event of collisions.

The vehicles will be inspected and, if deemed dangerous, will have a trailer hitch installed to their rears to protect tanks in case of accidents.

Grand Cherokees made between 1998 and 2004 will not be recalled as the NHTSA initially requested, as Chrysler has said they are safe to drive. The company will conduct a “customer satisfaction campaign” to inspect affected vehicles equipped with trailer hitches, which, if dangerous, will be replaced.

The recalls could cost Chrysler up to $300 million in installations.

Chrysler initially rejected the requests, blaming the NHTSA’s requests on “incomplete analysis of the underlying data.”

Auto manufacturers have approximately three years to bring their cars to market. Thorough testing to discover important design problems during that time can save on high maintenance costs.