A controlled gas is something many may not know about. But they exist, and at least one in South St Louis has been smelling since the summer according to one email.
These controlled leaks are basically leaks underrgound that ventilate out into open air. And since the gas doesn't collect in a contained space it's not considered dangerous.
What's more this can also happen in residential yards when a pipe gets a crack and gas leaks upand through the soil.
Laclede Gas will usuallyassess the leaks and determine if they're dangerous. This leak on Kingshighway is scheduled to be fixed in the spring.