N.S. probe into pharma worker's death finds vent hoods turned off in lab
Published Wednesday May 13th, 2009
HALIFAX, N.S. - An experienced pharmaceutical worker who died after exposure to a chemical that is "toxic if inhaled" was working under a ventilation system that was turned off because of roof construction, says the director of Nova Scotia's health and safety investigation unit.
The medical examiner's office hasn't finished its report on the cause of death, but the family of Roland Daigle say the 46-year-old chemist died in hospital on Oct. 7 after telling them he'd breathed in the chemical Trimethylsilyl Diazomethane while working at the Sepracor Canada plant in Windsor, N.S.
His sister Lynda MacDonald said Daigle told her he could still taste the substance in his mouth as he lay dying.
A week later, his family issued a statement describing their devastation over an excruciating eight hours of uncertainty as Daigle's symptoms shifted from those similar to having a cold to coughing blood, and eventually to retaining liquid in his lungs.
Jim LeBlanc, the director of the province's Occupational Health and Safety Division, said in a recent interview that Trimethylsilyl Diazomethane dissolved in hexane is "the product of interest" in the investigation of Daigle's death.
He also said the fume hoods, a standard piece of lab equipment which exhausts gases, were not working.
"The ventilation system had been shut down to accommodate some work that was going on on the roof," he said.
In a later interview, LeBlanc also said investigators are also looking into memos from managers at Sepracor that "indicated they wanted procedures restricted while the ventilation system was down."
He said the "facility had shut down the ventilation because of the roofing work, and it had also placed restrictions, or suggested restrictions, on activity because the ventilation system was down."
LeBlanc would not comment further, saying the precise nature of the restrictions is part of the investigation.
"There's a lot of judgment calls being made through this whole piece, and it's about decisions people were making," he said.
Jonae Barnes, the manager of corporate communications at the Massachusetts-based company, said that "as a matter of policy, Sepracor does not comment on matters actively under review."
"However, we remain unaware of any information establishing a link between Roland's unfortunate death and the workplace conditions at our Windsor facility," she wrote in an email.
LeBlanc said in general, ventilation is desirable when working with chemicals that release dangerous vapours.
"With any product, it's not just a question of what it is, it's a question of concentration and there's certainly a risk of exposure to higher concentrations if there isn't ventilation. ... If you don't use ventilation there's more risk of exposure," he said.
Derek Lowe, a chemist who has worked in research labs for three different pharmaceutical firms over the past two decades, said in an interview he was surprised at the lack of ventilation.
"It's terrible practice because chemistry labs in general have forced ventilation, we work inside fume hoods that are continuously sucking the air up and outside the building," he said from his office in Cambridge, Mass.
Lowe, who is also a columnist for Chemistry World magazine published by the Royal Society of Chemistry, said that Trimethylsilyl Diazomethane was created as a less volatile substitute for pure diazomethane, which he said exists as a gas and is explosive.
Lowe, who has been contacted by investigators and the family about the case, said he would have "refused" to have worked under such conditions.
The incident is also causing some scientists, and LeBlanc's investigators, to request a more detailed look at how toxic the substance is.
The Material Safety Data Sheet, an information sheet that manufacturer Sigma Aldrich provides, states the compound is "toxic if inhaled," and says it "may be harmful if absorbed through skin."
However, the sheet provided by the manufacturer also says there is little detailed information about the properties of Trimethylsilyl Diazomethane, stating "to the best of our knowledge, the chemical, physical and toxicological properties have not been thoroughly investigated."
LeBlanc said the death of Daigle has prompted his investigator to contact experts nationally and internationally about the toxicity of the product.
"We've talked to folks within agencies of the federal government," he said.
"There have been cases in the United States where concern was raised about the product. So certainly, it's a topic of discussion ... among producers of the product."
Daigle is the second chemist to die in a 12-month period after exposure to the chemical.
Jason Siddell, a 24-year-old chemist based in New Jersey, died after being exposed to the compound during his work on Jan. 4, 2008.
The medical examiner's report completed on Jan. 9, done with the assistance of a forensic pathologist, states he died due to "complications of a diazomethane compound exposure."
The report says Siddell had "massive" pulmonary edema, a build up of fluids in his lungs.
Paul Siddell said in an interview that his son had dropped a container of the Trimethylsilyl Diazomethane and it spilled on his clothing. He said his son died in hospital several hours after his exposure.
Dr. Nancy Murphy, a medical toxicologist and director of the IWK hospital's poison control centre in Halifax, said she has become concerned about the substance because she's seen references in chemistry textbooks that suggest Trimethylsilyl Diazomethane is less toxic than diazomethane.
While she agrees it is less explosive, she said it's premature to conclude it is less toxic.
"It has been touted as safer than diazomethane, and my belief is that it is not (safer) from a human toxicity point of view," she said in an interview.
Murphy has been working on a scientific paper on the topic since Daigle died.
Daigle's family issued a statement after being contacted by The Canadian Press about the updates to the case.
"We need to let the authorities do their work. The Daigle family has very high expectations of the Department of Labour's investigation report because it is their mandate to ensure people's safety while at work," Lynda MacDonald wrote in an email.
"We want to emphasize the importance of this investigation because of the possible changes it can bring to policies and legislation in the workplace. We want to ensure that Roland's untimely death will result in bringing about positive changes."
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