Under the Working Conditions Act, every employer is obliged to create the healthiest and safest possible workplace for his members of staff. Employers must therefore investigate whether there is a risk of suffocation, intoxication, poisoning, fire or explosion when containers are being entered and/or unloaded.This investigation must be carried out by a gas expert. The gas expert can only release a container when the measured gas concentration does not exceed the so-called MAC value. If it transpires that the container can be unloaded without this posing a danger, the expert will issue a free of gas declaration. So as to minimise the risk for members of staff, it is wise to test containers for the presence of poisonous gases before opening them.