In the US, trying to fight rats with dry ice

Dry ice - silent death for rodents

In a number of major US cities, rats are a major problem. This is especially true for the subway, parks, basements of houses, where rodents breed almost unhindered. Of course, there are special organizations to combat rats and mice, but they do not work as effectively as we would like.

The problem is not that these organizations work poorly, but that rats survive the baiting of even the most powerful poisons. Now there is a new way to fight rodents - dry ice. Yes, frozen carbon dioxide may well be an effective tool if it is placed in crowded places of rats.

Dry ice quickly melts, filling all the voids nearby with carbon dioxide. As a result, rodents die with entire families due to an overabundance of this compound.
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The pilot program was launched in August of this year, in Chicago. In March, a similar program to combat rats will begin to work in Boston, and in May - in New York.

"Dry ice" - is a solid carbon dioxide CO ₂ , under normal conditions (atmospheric pressure and room temperature) turns into a gaseous state, bypassing the liquid phase. In appearance it resembles ice (hence the name). The sublimation temperature at normal pressure is minus 78.5˚ C. It is produced in carbon dioxide plants. It is used for cooling food products (for example, ice cream) during their transportation and storage, in research works for obtaining low temperatures, during testing and assembly of some units in mechanical engineering, etc.

“When I first suggested using this method of baiting rats, people looked at me as if I were a cockatoo from the Cocos Islands,” says Leo Boucher, author of the idea. However, over time there were quite a few supporters of this idea, and it was decided to implement the project.

Frozen carbon dioxide is placed in rat holes, the outlets of which are closed to prevent rodents from escaping. Work is carried out in the early morning when these animals are the least active. The results, according to the project participants, are promising.



“We saw a 60% decrease in the number of rat holes in areas where dry ice was used,” says Charles Williams, a Chicago administration official. "Carbon dioxide does not harm the environment." In addition, fighting rats with CO ₂ is one of the most humane methods.



After the completion of the pilot phase of this project, the fight with rats using dry ice will be in other major US cities. The number of rats in a number of settlements began to grow very actively. Among those cities where there is a rapid growth of the population of rodents - Boston, Chicago, New York and Washington.

Rats have become more due to the relatively mild winter of 2015-2016. Especially a lot of them became in regions with a warm climate. US scientists at the request of the government began to develop a program to combat rats. Officials considered the project using dry ice to be the most interesting and promising project. With the help of computer systems, experts identified the foci of rat distribution, and began to work most actively there. Several dozens of criteria for the development of a rat population were also identified.

Dry ice has already shown itself to be a more effective means of rodent control than conventional pesticides. And it is cheaper. The cost of dry ice in Chicago is only about 60 cents per 0.5 kg. But the packaging of toxic chemicals to fight rats costs about $ 57 per package weighing 9 kg. In Boston, the cost of dry ice is even lower - just 25 cents per pound. Employees of public services use about 1.1 kg of dry ice for each detected hole. Now works are carried out only in parks, playgrounds, cemeteries.

As an example of the effectiveness of the new method of rodent control, we can cite the work of specialists in one of the parks in New York. 368 burrows of rodents were noticed here, in which workers put dry ice. By the end of the test period, only 20 active holes left in the park. In the other of the parks of the 60 holes, only two remained active.

What the officials decided to introduce and another way to deal with rats - cat-rat. So far, this second project is at the development stage.

The administration of Boston and Chicago declares that they will use not only dry ice to fight rodents. Traditional poisons will also be used. But their number is planned to be reduced to the necessary minimum. "The pilot project for working with dry ice showed excellent results in the parks of New York," - said in a statement the health department of this city. "We continue to work with the new method."

In Boston, the number of residents' complaints about rats has tripled in the last quarter of this year. After consulting with scientific experts, the city administration decided to test carbon dioxide. This method is widely used in the laboratories of various scientific organizations for the rapid killing of laboratory animals. High concentrations of carbon dioxide lead to loss of consciousness in rats for one minute. After some time, death occurs.

The advantage of this method of rodent control is that carbon dioxide does not become part of the food chain. For example, a poison that is used to eliminate rats often causes the death of birds, soil fauna and a number of other creatures. Carbon dioxide, however, acts exclusively locally, without extending to neighboring food chains and without killing many “untargeted” organisms.

In addition, rats do not feel the increase in carbon dioxide concentration until it is too late. But poison, in most cases, they feel, and very well.