While Extension doesn't collect information on business practices (nor do we make company recommendations), we can say that the simplest and most effective approach in the long term is to exclude the wasps from nesting sites of interest. Thus, sealing gaps and cracks with expanding foam, caulk, or any other appropriate material will discourage them from exploring any nooks and crannies for nesting without having to rely on pesticide applications later.

Social wasps (yellowjackets, hornets, and paper wasps) do not re-use nests from year to year, so must start a new one from scratch each spring (one female does this by herself). If multiple females are active in a given area, then they must be finding suitable nest sites, though we doubt yellowjackets would tolerate another nest so close together. Might you have mud dauber wasps (like this pipe organ species) instead? Are any parts of the nest(s) visible, and if so, are they made from paper or mud? If you happen to have mud daubers, they are not social wasps and are rarely defensive of a nest, so are useful to keep around since they pollinate flowers (as do the yellowjackets) and catch insects or spiders that gardeners consider a nuisance or pest.

Pesticides must legally be used in the manner in which their label details, so applications following instructions should pose minimal risk to other organisms and people. Many pesticides also degrade relatively rapidly once exposed to sunlight, rain, soil microbes, and other environmental conditions, so contamination of other habitats in the area is less likely, especially when applications are targeted to just the entrance hole for a communal wasp nest. Insecticide for wasp nest should be the last resort, though, if exclusion techniques are not working or not feasible.

Miri