Newborn baby less than a month old living in home with gas leaking from stove. the stove gas has been shutoff now, but could the baby face long term effects from this? tech detected the leak at less than 1 percent but worried he breathed it so long?

Wouldn't think so: Any inhaled gasses were also exhaled the same way. I think the kid would have more trouble with house dust or perfumes than gas at that level. I would not find it likely to have any long term effect on baby at all.

Developing lungs: The lungs are still developing at this age, and it is important to keep smoke and irritants away from the baby. The exposure to a stove gas leak without smoke is less likely to injure the lungs. Watch for signs of cough, sweating, and rapid breathing. If these occur, please see the ED.