Any work that is unfamiliar should be regarded as potentially of high risk
Carrying out a comprehensive Risk Assessment will show if the task is within your capabilities and resources. If there is any doubt, seek professional advice about the work.
Do not allow anybody to undertake any work that may be a risk to themselves, or to others, until they have been trained and have satisfied a competent person of their ability to perform the work safely and efficiently.
Likewise, working in a confined space requires special attention. A confined space can be any space that is enclosed, where there is a risk of death or serious injury from hazardous substances or dangerous conditions, e.g. lack of oxygen, poisoning, explosion or fire.
Some confined spaces are easy to identify, e.g. enclosures with limited openings:
Others are less obvious, but can be equally dangerous, for example:
The handling and storing of certain types of chemicals may also present a high risk to the person doing the task and may cause damage to the environment if spilt.