What really is meant by a ‘Substantial Threat’ of Pollution? - an examination of the term’s meaning in the United States and elsewhere

Abstract

ABSTRACT 2017-392 The term ‘substantial threat’ appears in the statutory text of the US Oil Pollution Act of 1990 (OPA 90), and has played a key role as an important triggering mechanism for the operation of the Act in many prospective spill events. Yet this important term is not defined at all in the Act itself. This paper examines the meaning of this term, looking at other sources of possible definition, including plain language/dictionary meaning, court cases, the decisions of the US National Pollution Funds Center, and other materials. One way to define ‘substantial threat’ of pollution would be a situation where the risk of a spill is greater than the normal risk posed by a particular vessel in a particular place – but this paper will examine if that possible definition fits with the actual practice and experience of the term. In order to attempt to address that question, we will examine how the US Coast Guard has used this concept in cases in recent years. The statutory concept of ‘threat’ is also used outside of the US, and the second full section of this paper continues with a discussion of how this concept exists in other countries as to their approach to possible spill events, and how that may differ from the US approach. The conclusion from the examination of US and non-US terms is that the current ‘ad hoc’ use of the term, without a rigid meaning, is the best approach.