Soldiers were put at risk of harm in testing the new £5.5bn Ajax armoured vehicle, which was so noisy that troops could suffer hearing loss, the defence procurement minister has told MPs.

Jeremy Quin said 11 soldiers had to be placed under long-term monitoring following a catalogue of “complex and systemic” failures. He admitted the episode showed the army did not place as high a value on safety as cost and value for money.

A string of warnings about excessive noise and vibration dating back three years were not properly acted upon, the minister said. “It lays bare a deep malaise which is cultural and results in systemic failures across our organisations,” Quin told MPs on Wednesday.

Further details were spelled out in a health and safety report published by the Ministry of Defence in conjunction with Quin’s statement to MPs. It said: “Safety is not viewed as an equal partner to cost, schedule and military capability” – and that the army felt that soldiers had to put up with discomfort as part of the job.

The MoD first decided on Ajax in March 2010, and awarded a contract to the US military contractor General Dynamics. At the time it believed there was a 50% chance the vehicle would enter service in 2017 but more than 11 years later it is still being tested as the manufacturer tries to reduce noise and vibration.

Eleven people out of 310 who tested Ajax now have “long-term restrictions on noise exposure recommended” following a medical assessment, while 17 remain under specialist outpatient care. A further four were discharged from the army on health grounds, although in some cases for unrelated reasons.

Military chiefs want to buy 589 of the armoured vehicles, which Quin told MPs would cost £5.5bn. According to a National Audit Office review of defence projects published last June, the MoD has spent £3.75bn out of the whole-life cost budget of £6.3bn.

Despite the long-running problems, Quin said the MoD hoped to resolve the problems by working with the manufacturer in the coming months. But he offered no timing or certainty that the efforts would succeed in resolving one of the military’s worst continuing procurement crises.

“It remains impossible to share with this house 100% confidence that this programme will succeed, or if it does the timing of achieving full operating capability,” Quin said. The backbencher Tobias Ellwood, the chair of the defence committee, called on ministers to make a final decision in February.

Quin also said the MoD would appoint a senior legal figure to lead a review of the Ajax procurement which would cover “not just health and safety” but “the cultural and process flaws that it has highlighted”, in particular the fact it was “tacitly expected that soldiers can and should endure such issues”.

Labour said the government’s response left Ajax in limbo. John Healey, the shadow defence secretary, said: “It is deeply unsatisfactory that the action following this review is to launch another review.” He told MPs the suspicion was that the project had become “simply too big to be allowed to fail”.