The new coronavirus can survive long exposure to high temperatures, South China Morning Post reports, citing an experiment by a team of French scientists.

Professor Remi Charrel and colleagues at the Aix-Marseille University in southern France heated the virus that causes Covid-19 to 60 degrees Celsius (140 Fahrenheit) for an hour and found that some strains were still able to replicate.

The scientists had to bring the temperature to almost boiling point to kill the virus completely, according to their non-peer-reviewed paper released on bioRxiv.org on Saturday. The results have implications for the safety of lab technicians working with the virus.

The team in France infected African green monkey kidney cells, a standard host material for viral activity tests, with a strain isolated from a patient in Berlin, Germany. The cells were loaded into tubes representing two different types of environments, one “clean” and the other “dirty” with animal proteins to simulate biological contamination in real-life samples, such as an oral swab.

After the heating, the viral strains in the clean environment were thoroughly deactivated. Some strains in the dirty samples, however, survived.

The heating process resulted in a clear drop in infectivity but enough living strains remained to be able to start another round of infection, said the paper.

There are now more than 2 million cases of the novel coronavirus worldwide, over half a million of which have recovered, according to Johns Hopkins University, which is tracking figures from the World Health Organization and additional sources.

Since the beginning of the outbreak, more than 138,000 people have died globally from Covid-19 complications.