BP PLC has applied 272,000 gallons of dispersants to the surface of the Gulf of Mexico in the four weeks since U.S. EPA and the Coast Guard directed the company to stop using the chemicals, except "in rare cases" when other approaches to fighting the ongoing oil leak proved unworkable, according to government records.

The oil giant's dispersant strategy has come under scrutiny from scientists who warn that adding unprecedented volumes of the chemicals to the Gulf environment could pose unknown risks to human and marine health. But the surface use of dispersants, in some cases spread aerially by planes, stirs a specific worker-protection concern for National Institute for Occupational Safety and Health (NIOSH) Director John Howard.

"From a health and safety perspective, I'm not a fan of dispersants" sprayed from the air, Howard told Greenwire. "Unless you make sure you don't have workers underneath the spray. That would be great."

Controversy over BP's compliance with the May 26 directive (pdf) issued by EPA and the Coast Guard on dispersant use flared anew this week when Richard Denison, a senior scientist at the Environmental Defense Fund, released calculations that showed the oil giant had cut its average daily dispersant use by 68 percent relative to the previous daily maximum levels. EPA had set a 75 percent reduction as the "overall goal" for the company.

A separate portion of the EPA directive, however, told BP to "eliminate the surface application of dispersants." The company was required to file a written request to the Coast Guard seeking permission to use surface dispersants "[i]n rare cases when there may have to be an exemption," citing the particular weather or mechanical factors that were forcing the use of chemicals to break up oil, as opposed to skimming or burning.

The Joint Incident Command in New Orleans did not respond to several requests for a copy of the written justification that BP is required to provide before using surface dispersants. A request that BP release the document was not answered by publication time.

Wilma Subra, a Louisiana chemist who has assisted local environmental and public-health groups since the Gulf spill began, said she and her partners "were getting lots of reports from workers that they were being sprayed [by dispersant] and getting assurances by a bunch of high-up national officials that they were taking tons of precautions, that no one was being sprayed."

Symptoms experienced by the workers included headaches and nausea as well as skin, eye and respiratory irritation, according to Subra. Despite the government's assurances, she added, "we continue to get calls ... [workers] are very reluctant to seek medical care because they are afraid to lose their jobs."

As of Tuesday, daily reports from the JIC and EPA show that BP had applied 272,000 gallons of surface dispersant since EPA's May 26 directive, compared with 342,000 gallons of sub-surface dispersant.

EPA spokeswoman Adora Andy released a statement yesterday that affirmed EPA's ability to secure a reduction in overall dispersant use since the directive was issued to BP. "On the evening of May 23, Administrator [Lisa] Jackson and Coast Guard Rear Admiral [Mary] Landry sat down with BP and ordered them to ramp down dispersant use -- with an overall goal of 75% from its peak usage of 70,000 gallons on May 23," Andy said.

"The next day, May 24, dispersant use dropped more than 50%. Since Administrator Jackson and Admiral Landry met with BP on May 23 to demand a reduction, dispersant use is down 68% from its peak," Andy said in the statement.

Andy's statement also addressed the continuing use of surface dispersant, noting that the Coast Guard "has the authority to grant waivers for the use of more dispersant based on changing conditions at sea."

The ingredients in BP's Corexit 9500 dispersant, now the primary chemical product used to break up the oil into smaller droplets, include the common solvent propylene glycol, light petroleum distillates and the detergent dioctyl sodium sulfosuccinate (Greenwire, June 9). Material safety data sheets released by Corexit's manufacturer identify the three substances as potentially hazardous, advising users to avoid getting the dispersant "in eyes, on skin, on clothing."

The Occupational Safety and Health Administration (OSHA), which enforces worker-safety standards onshore and near shore in the Gulf, continues to affirm that its tests show no risk of unsafe chemical exposures among responders to the spill.

Jordan Barab, deputy assistant secretary at OSHA, told reporters yesterday that his agency is monitoring "on the beaches, in the swamps, on the boats, everywhere that workers are. ... [W]e have found no exposure levels to any chemicals that are of any concern."

Copyright 2010 E&E Publishing. All Rights Reserved.