Mercury contamination at some rigs on par with Superfund sites
By BEN RAINES
Mercury contamination at some oil and gas rigs in the Gulf of Mexico appears to be so severe that the rigs could qualify for the National Priorities List, a roll call of the nation's most hazardous contaminated sites.
Placement on the National Priorities List -- which would ultimately depend on approval by federal agencies -- can eventually lead to a federal "Superfund" clean-up effort, like those at Love Canal in New York and at Cold Creek Swamp and the Olin Basin in south Alabama.
But federal officials say that the rigs are unlikely to ever make the list -- in spite of any hazards they may pose to humans -- because at least some of the contamination might have been the result of federally permitted releases of pollutants.
The Mobile Register found that the rigs could warrant a place on the National Priorities List by applying formulas outlined in the U.S. Environment Protection Agency's widely available Hazard Ranking System and its supporting PreScore computer program, which the agency relies on when examining potential Superfund sites.
The Register's Hazard Ranking System calculations showed that:
The well-documented contamination in the sediments beneath some rigs reached the Hazard Ranking System's maximum value for observed releases of hazardous pollutants.
Mercury concentrations in many fish and shellfish sampled around at least one of the rigs were high enough to qualify the area as a contaminated fishery.
Frequent use of the rigs by commercial and recreational fishermen means that the contamination around the rigs represents "a human food chain threat."
Federal officials who reviewed the Register's data said there's little chance that any agency would attempt to put any of the 4,000-odd Gulf rigs on the Superfund priorities list, regardless of the level of contamination.
They also questioned whether the intricacies of the laws governing the National Priorities List would apply to the contamination around the rigs, particularly since the contamination occurred as a result of on-going, federally permitted releases of pollutants.
But they acknowledged that the government has regulatory authority over offshore rigs and that the contamination could be a serious issue meriting further studies to determine the possible risk to people who eat fish associated with the rigs.
"There probably is some human health risk there. I think there is an issue here," said Ron Gouguet, the National Oceanic and Atmospheric Administration's coastal resource coordinator in Texas, who was asked to review the Register's PreScore data by EPA officials. "To find out how big an issue this is, we'd have to test around some rigs and do a risk assessment."
He also said he believed that the rigs would easily pass the benchmarks to qualify for the National Priorities List, because the government data he reviewed shows elevated mercury levels in sediments around the rigs and in the tissue of fish and shrimp that people eat.
Gouguet said that, given the toxicity of mercury and the fact that its dangers are magnified as it moves up through the food chain, the contamination beneath the rigs and in the creatures around the rigs would score a 50 "right away" in the official hazard ranking system.
A rating of 28.5 qualifies a site for the National Priorities List. The Register's most conservative calculations yielded a score of 42 for the most contaminated rig.
"I'm passing this data around to show that this is a large issue," Gouguet said.
EPA officials were reluctant to talk about the rig contamination in the context of Superfund laws. But Brenda Cook, who handles Superfund investigations along much of the Gulf Coast for EPA, told the Register that EPA scientists had examined the data and were distributing it to other federal agencies.
"After I reviewed the data, personally from a scientific viewpoint, yes, a problem might exist. Some contamination is apparent," Cook said.
The Register began investigating the criteria for the National Priorities List when it became apparent that mercury contamination around some rigs was on par with mercury levels found in some heavily contaminated areas, like Lavaca Bay on the central coast of Texas, that are already designated Superfund sites and have been long closed to fishing.
When EPA looks at potential Superfund sites, it has a formula -- the Hazard Ranking System --for determining how serious the contamination is. This formula and its accompanying PreScore computer program are available to the public through the EPA's Web site and elsewhere.
The Register attempted to hire a number of environmental consulting firms to run the data from the rigs through the Hazard Ranking System, but all declined, citing potential conflicts with oil industry clients. Several state environmental agencies also declined to run the numbers.
But the Hazard Ranking System is designed to simplify identification of potential Superfund sites, and comes with its own on-line training course, which makes it possible for environmental consultants and other non-government groups to use the formula. Before a site could be added to the National Priorities List, EPA officials would have to review the results and make the final determination.
The Hazard Ranking System requires the user to show not only that contamination levels are high and that the pollutant is toxic, but it also requires a determination of whether the contamination has the potential to enter the food chain. Finally, and perhaps most importantly, the ranking system requires that the user determine whether humans are likely to be exposed to the hazards posed by the contamination.
On all counts, the rigs would qualify, the ranking system shows.
A U.S. Minerals Management Service study of three representative rigs in the central Gulf of Mexico revealed that sediments around two of the rigs had mercury levels many times higher than levels in uncontaminated Gulf sediments. One of the rigs studied had levels hundreds to thousands of times higher. MSS is the federal agency that regulates the nation's offshore oil and gas fields.
The scientists who conducted the study determined that the millions of pounds of drilling muds used at those wells, and largely dumped overboard after use, were the cause of the contamination.
The MMS data also showed that average mercury levels in shrimp around the most contaminated rig were 25 times higher than average mercury levels found in shrimp from Mobile Bay and Mississippi Sound, according to data from the MMS and EPA. The rig with the most sediment contamination also produced fish and shrimp samples that were up to five times higher than samples from the least contaminated rig, an indication that the mercury could be working its way up the Gulf's food chain.
But the Hazard Ranking System yields the highest scores for a polluted site when a toxic substance such as mercury has the potential to enter the human food chain. The potential dangers of the mercury pollution may be magnified due to the number of commercial and recreational fisheries intimately tied to the rigs, which make up the largest artificial reef system in the world.
The rigs -- thousands of them -- lie in some of the most productive waters of the Gulf, according to data from the U.S. National Marine Fisheries Service.
At any point along the Gulf of Mexico, from Mobile Bay to the Mexican border, the rigs twinkle on the horizon like lights from a distant city. But the rigs visible from the beach represent a tiny fraction of the total in Gulf waters, where the rig fields extend 200 miles from shore.
Thousands of recreational fishermen head for the rigs every time they go fishing, launching their boats from places like Dauphin Island south of Mobile, from Venice and Port Fourchon in Louisiana, and from Galveston in Texas.
One study posted on the Minerals Management Service Web site states that 70 percent of all offshore fishing trips originating in Louisiana target the oil rigs. Saltwater fishing magazines are full of articles about rig fishing, and the Alabama Marine Resources Division's most recent calendar devotes the month of December to a spread on fishing the rigs.
In many places, particularly off the coast of Louisiana, it's almost impossible to go fishing without being in sight of a dozen rigs. Fishermen get as close to the rigs as possible, often tying their boats to them. The reason is simple: The massive steel structures swarm with fish.
An MMS press release describes the rigs as "oases for marine life in the Gulf."
"Without the platform and other artificial reefs, fish and other marine life typically would become widely dispersed, far from ideal conditions for commercial fishing and recreational fishing," reads the release touting the benefits of the rigs. "These platforms serve as hunting grounds for swift open-ocean pelagic fishes, such as mackerel, tuna, and jacks."
Dozens of studies posted on the MMS Web site document the fish-attracting powers of the rigs. Each rig supports colonies of up to 30,000 fish, according to those reports, and the dominant species at the rigs are some of the Gulf's glamour species, including snapper, grouper, amberjack and triggerfish.
Data from annual National Marine Fisheries Service trawl surveys indicates that the rig fields off Louisiana and Texas are the richest waters in the western Gulf for reef fish such as red snapper.
The MMS studies show that fish densities around the rigs are up to 1,000 times higher than in the surrounding Gulf waters. That means the fish are concentrated where MMS sediment samples indicate mercury levels may be highest.
It's clear the commercial fishermen also know the rigs are covered in fish. A sign posted at the New Orleans Aquarium of the America's oil rig exhibit states that 75 percent of Louisiana's commercial and recreational seafood harvest comes from the waters around the rigs.
Louisiana is the undisputed king when it comes to bringing in Gulf seafood, with an annual harvest worth over $100 million, more than any other Gulf state. Taken together, the Gulf's oil- and gas-producing states, Alabama, Mississippi, Louisiana and Texas, account for at least 90 percent of the total Gulf harvest.
These fish could well end up at fish markets or restaurants around the country: The U.S. Food and Drug Administration does not conduct any widespread mercury testing of domestically caught fish.
While federal officials acknowledged the contamination at the rigs may be high enough to set the Superfund process in motion, they said it is unlikely any of the Gulf's 4,000 rigs will ever be listed as Superfund sites. In fact, EPA officials said the Superfund rules cannot be applied to the rigs because the oil industry has EPA permits that allow them to discharge the contaminated drilling muds, as long as mercury levels in the discharge remain below certain levels.
"We may not have authority because they are permitted releases," said the EPA's Cook. "While they are still active, permitted releases, we are not able to address them under CERCLA," which are the federal rules governing Superfund designations.
Scientists have tested only a handful of Gulf rigs, but it's apparent that the processes that caused contamination at those rigs are standard within the industry.
The oil industry dumps over a billion pounds of mercury-contaminated drilling mud wastes into the Gulf each year. Drilling muds are used to cool and lubricate drill bits as they bore into the earth while plumbing for oil and natural gas. The mercury is present in an element called barite, the main ingredient in the muds.
In 1996, the EPA limited the amount of mercury that could be present in the drilling muds to 1 part per million, which could still allow 1,000 pounds of mercury to be dumped from the Gulf platforms each year.
For nearly 50 years, prior to the EPA rule, there were no limits on mercury in barite. A report published by the Society of Petroleum Engineers suggests that in the past, barite with mercury at up to 30 parts per million could have been used.
Mobile Register calculations using information supplied by the oil industry and the EPA suggest that hundreds of thousands of pounds of mercury may have been dumped in the Gulf -- via drilling muds -- since the 1960s.
Scientists who conducted the MMS studies say that at the rigs they've tested, the mercury contamination has persisted at high levels for years, and will likely remain high for decades.
The oil industry and the Minerals Management Service have repeatedly insisted that the mercury at the rigs is not a concern.
"We are concerned about the health of people in the Gulf region," said Dian Lawhon, a spokeswoman for MMS, in a telephone conversation last week. "Even though our scientists do not see any health concerns arising from the data we've collected, we are asking a board of independent scientists who are advisors to MMS to review the data and make a recommendation to MMS as to whether we should do more research."
The data MMS plans to review is the same data the Register supplied to EPA and NOAA.