The resilience of German cockroaches is no myth. Their diet consists of basically anything, from actual food to flakes of skin and wallpaper. They’re small enough to squeeze out of sight. They can produce up to 400 offspring in a single year. And they laugh at bug bombs for houses.

According to a new study, bug bombs are not only ineffective at killing German cockroaches; they’re probably more dangerous to other occupants of the residence. Namely, you.

The study, conducted by North Carolina State University entomologist Zachary DeVries and published in BMC Public Health, recently shed some light on the issue. DeVries and his team solicited the participation of 30 residential homes with documented cockroach infestations and used gel bait traps in 10 of them. For the rest, researchers used total release foggers, also known as a bug bombs, that release airborne pesticides affecting a bug's nervous system. To assess the efficacy of each, cockroaches were captured and kept near the site of the treatment to maximize the chances of the bugs receiving exposure to them.

Within a month, the gel bait traps reduced German cockroach populations in treated homes by two-thirds or more. Homes treated with bug bombs had no discernible effect on the roaches. Some sites actually saw an increase in the bugs.

German cockroaches have a sturdy constitution when it comes to poison. The bug bombs, researchers noted, are no guarantee of providing a toxic plume even if it reaches the roach. And even that can prove difficult, since the bombs can’t spread through all areas of the house where the bugs might be found. Gel bait traps entice the cockroaches to enter by offering a sweet smell. Consumption of the poison or entrapment results in mass cockroach expiration.

Aside from being a waste of money, bug bombs carry a secondary threat of being toxic to humans. The release of chemicals into a living space can be irritating for some, with the Centers for Disease Control and Prevention documenting several cases related to exposure. Sometimes, people overestimate the number of bombs needed, saturating their indoor living space with breathable chemicals. They can also leave residue on surfaces like kitchen counters.

Ultimately, gel bait traps are a reasonable solution for mild infestations. If your problem is so severe you’re considering bombing your house with chemicals, it’s probably best to call a professional instead.

[h/t Gizmodo]