Engineering is a profession. Engineers do not see themselves merely as the employees of large organizations but as independent practitioners with a culture and set of practices all their own. As part of the development of the profession, engineers have established a general set of ethics to follow. As in all craftwork, there are certain engineering standards to meet and common considerations of design and use for the consumer.
Engineering took on much more importance in everyday life after the Industrial Revolution. Large-scale engineering projects came to dominate the landscape of most major countries. Highlighting the importance of solid engineering were the structural failures of several notable landmarks, such as the Quebec Bridge in 1907, which cost many lives. Engineering ethics began to take on a supreme importance in this way, as people learned that lives depended on a well-crafted design.
Similar to the Hippocratic oath in medicine, the first duty of the engineer is to protect the welfare and safety of the public -- do no harm. This means being completely certain of the integrity of any structure and thoroughly testing the safety of any product, even if there is temptation to cut corners or overlook a concern that would be inconvenient. The purpose of establishing professional ethics is to enforce a minimal standard.
There is no excuse for an engineer if she says she allowed a faulty project to go through because she was obeying orders. All engineers have the duty to report any faulty engineering of which they are aware. If an organization refuses to take the necessary steps on its own to fix a problem, it is the duty of the engineer to be a whistle-blower and report the organization to the proper government authorities.
As engineers became more prominent and important to society following the Industrial Revolution, many different engineering societies came about. These societies generally follow a certain specialization of engineering, such as the Institute of Electrical and Electronics Engineers. Such organizations seek very prominently to promote ethical concerns within the field, and they typically have an explicit code of ethics they expect all members to follow. Members can be expelled if they are found in violation.