I expressed doubts

...

I’m very confident

which is reasonable with the given information

no it's not.

Just because a city stops providing a service has absolutely no bearing on whether or not they follow federal laws. In fact reducing those other service was maybe done so that they could continue to follow federal regulations. That's more likely than "city cuts one service so they must be breaking federal laws". Your logic would have made more sense if you literally went the opposite direction with it. "City cuts services so it can focus on federal requirements, since other services were costing the city money and taxpayer revenue isn't high enough to cover supplemental services"

But this is of course all speculation because nobody knows which place this is about our OP might have just made it all up.

and we can at least speculate with logic. If a city is cutting services, it's probably because they need to fund other (required) things. If a city is in the USA (which it sounds like from OPs comment) then they have to follow federal regulations. If the city was doing what OP said they would be breaking SO MANY federal regulations that OP should report them. What is entirely more likely is that the city is following federal regulations, none of the oil OP put into the trash made it into groundwater, and that if it did, OP should be reporting the city to the EPA (which fines hundreds of millions for violations like this).