Critics of the Army's plans for destroying nerve agent at the Umatilla Chemical Depot are no doubt feeling their concerns have been reinforced. That's because on Wednesday a mechanical glitch brought a halt to disposal of the very first rocket to be fed into the giant new incinerator that was built to get rid of the deadly weapons.

But the abrupt work stoppage is reassuring. It shows that at the first sign of trouble on this difficult project, the Army and its contractors performed true to their promise of going slow and putting public safety first.

What went wrong? A trap door failed to open and release chopped-up parts of an M-55 sarin rocket into a furnace. Technicians in protective suits will probably have to enter the contaminated area to troubleshoot the electrical and hydraulic systems that failed.

Sounds pretty scary, "China Syndrome" imagery and all. Yet it was exactly the kind of thing we were told to expect in this half-a-billion-dollar undertaking, and it was the kind of careful -- and publicly disclosed -- response we were counting on the Army to take.