In a legal sense, omissions can come up in two different contexts. The first and more serious context involves failure to perform activities which one is legally obligated to do. This type of omission can result in legal liability if someone experiences an injury as a result of the omission. The other type of omission involves leaving something out of a legal document; if the omission is the result of a mistake on the part of all parties involved, the document can be rewritten by agreement.
Neglect of duty can be a very serious form of omission which may result in serious injury or damages. For example, if road workers have removed an access panel to get into an area under the road and they fail to hang signage, this is considered an omission. If someone falls into the exposed area and is injured, the road workers will be liable because they failed to do what the law requires them to do in order to protect people from harm.
Omissions can include not performing a wide variety of tasks, ranging from maintaining safety equipment to hanging warning signs. If it can be demonstrated that these duties are obligated, as is often the case when people are contractually obligated to perform them, these omissions can be grounds for lawsuits. Cases in which someone was not required to do something or did not know about it due to inadequate training or support may be more difficult to resolve.
Failure to act can also occur in situations like traffic accidents. If someone causes an accident as a result of an omission, as for example when someone fails to brake as traffic ahead slows, she or he can be considered legally liable for the injuries incurred. The law generally determines that people have a duty to avoid dangerous situations and to take action if someone is in danger, which means that failure to do so can have legal consequences if injuries occur.
In written documents, an omission is often a mistake which is innocent in nature and unintentional. The document can be amended or altered by the agreement of everyone involved to correct the omission. There may also be cases in which someone makes a deliberate omission with the goal of changing the meaning of a document and in these situations there may be liability issues. It is advisable to review final versions of documents before signing them so that any problems such as omissions can be identified.