Are “this lawn chemically treated” signs a scam?

Dear Cecil: Recently a condominium in my neighborhood put signs on their front lawn reading, “This Lawn Is Chemically Treated--Keep Pets Off.” I’d like to know, chemically treated with what? That is, if it’s chemically treated at all. I have a hunch that there is nothing on the lawn at all and the signs are there to scare away people walking their dogs. If the lawn is treated with something, what most likely is it, and what does it do to the animals? Also, if an animal or child is poisoned or harmed by the chemicals, aren’t they responsible? Is there a company or something that goes around treating lawns and sticking up ominous signs to keep dogs off? J.K., Washingtom, D.C.

Cecil replies:

Dear J.:

The chemical used may be, as you suspect, no chemical at all, or it may be any of a myriad of herbicides and pesticides. Assuming, for the sake of argument, that there is a real chemical there, and assuming it is not prohibited for use near residences by the federal government, and assuming that the landscaper who put it there has followed the directions for dilution, application, etc., specified for the product’s use, and assuming that the treatment is not being repeated every two days or so . . . assuming all these things, none of which is a very risky assumption, there’s a good chance that the sign is pure hokum.

Some commonly used lawn-treatment chemicals are toxic–2,4-dichlorophenoxyacetic acid, a broadleaf weed killer, is a good example. But when they’re used properly their danger passes within 24 hours or so as they are washed or absorbed into the soil.

Even in the few cases in which signs like this warn of real danger, the chemicals referred to are put there to treat the lawn rather than to chase or harm animals. Anti-animal preparations do exist, but their purpose is to chase only, and they are harmless.

One particularly charming concoction consists of napthalene (in harmless amounts), tobacco dust, and dried animal blood. The blood attracts the offending varmint to the site so it can be scared away forever by the tobacco dust (which causes sneezing) and the napthalene (which causes an unpleasant tingly sensation in the genital area–I told you this stuff was charming). As devious as all this may seem, the product–like others that work on the odor or taste principle–cannot harm any person or thing that eats less than 70 or 80 pounds of it.

So yeah, maybe this “chemically treated” business is just a cheap psychological ploy calculated to make you keep your dog off the lawn. Having scooped a fair amount of dog poop off my lawn without ever having owned a dog, I think it’s a wonderful idea.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.