Cat safe weed killer?

[Mumsworkneverdone]

Hi , my neighbour has emplyed a gardener to Help remove weeds in the gravel in their garden . However she's kindly mentioned she's hesitant to use poison as one of my cats frequently sits and walk through her garden. Can anyone recommend any professional weed killers (not salt or vinegar please) that are safe for cats?

Many Thanks in advance!

They're all supposed to be ok once the weedkiller has dried so if she lets you know when it's being applied you can keep the cat in until it's no longer wet.