Environmental Monitoring

Structure Removal

Lessees/operators must submit for approval an application to the BOEMRE for a structure removal and provide information including the following: complete identification of the structure; size of the structure (number and size of legs and pilings); removal technique to be employed (if explosives are to be used, the amount and type of explosive per charge); and the number and size of well conductors to be removed and the removal technique (LTL's dated August 19 and December 9, 1986). Structure-removal requests are reviewed on a case-by-case basis. At present, all structure removals require an environmental assessment by the BOEMRE and if explosives are used, require an Endangered Species Section 7 Consultation with the NMFS. The NMFS issued a "standard" Biological Opinion on July 25, 1988, which covers removal operations that meet specified criteria pertaining to the size of explosive charge used, detonation depth, and number of blasts per structure grouping. The BOEMRE, the NMFS, and lessees are cooperating in an observer/monitoring program to determine the presence of marine mammals and/or sea turtles in the vicinity of the structure removals. Additional information on structure removals is found in Section IV.A.2.a.(4).

The use of explosives to cut offshore oil/gas structure legs/pilings for removal could cause injury or death to protected marine mammals and endangered sea turtles. Although the NMFS has the sole responsibility to enforce protection of the majority of marine mammals in the Gulf, BOEMRE and NMFS have conferred extensively in the development of platform removal precautions and have employed data resulting from equations found in Connor (1991). Regarding "uncertainties concerning the possible effects of structure removals . . .," the NMFS has instituted a comprehensive program to protect sea turtles and cetaceans. The NMFS sends observers to every structure removal where explosives are used. The cumulative information gathered by observing these removals address the uncertainties about direct mortalities or injuries to marine mammals resulting from these removals (none have been documented since these observations begun in 1986). Since the NMFS protective observer program began in 1986, only one sea turtle is known to have been harmed with certainty. Others have been removed from platforms slated for removal, prior to detonation. If cetaceans are observed in the vicinity of a removal site (they are much more visible and obvious to observers), detonations are postponed until the animals have vacated the area. The NMFS is totally responsible for training observers to their own required level of expertise and believes it would be redundant for BOEMRE personnel to engage in the observer program (Gitschlag, personal communication, 1994). While BOEMRE observers have been on site during removals, none have been employed directly as formal observers, recorders of data, nor in an advisory or decision-making capacity.