Alex Hummell says few dentists seem worried enough about invisible, odourless mercury to take the kinds of precautions needed to prevent everyday exposures.
As the head of a Littleton, Colorado firm that sells sophisticated equipment to gauge airborne levels of highly toxic mercury at industrial sites worldwide, Hummell has watched manufacturers of all sorts put their employees through strict training programmes in which they don special equipment to avoid even tiny exposures.
Then he walks into dental clinics and is dumbfounded.
On numerous occasions, he said he has detected mercury levels in dental offices that were two to three times the average workday exposure limit of 100 micrograms per cubic meter set by the Occupational Safety and Health Administration, but patients and the staff were wearing little or no protective equipment.
“I’ve seen in dental offices what would make these other offices have to shut down,” said Hummell, CEO of Mercury Instruments USA Inc. “They would be closing their doors and getting respirators on.”
Instead, he said, “there are kids running around everywhere. It’s the exact same toxin, and it’s being treated totally differently. Why is it being allowed to be so unregulated?”
OSHA requires dentists with one or more employees, like any other employer, to ensure their offices are free from “recognised hazards likely to cause death or serious injury.”
Dentists must provide employees with annual training and a list of all chemical agents stored in their offices, as well as a copy of manufacturers’ Material Safety Data Sheets, which spell out the health risks of mercury, which comprises 50 per cent of dental amalgams.
Hummell said his other customers monitor mercury levels at their work sites, as required by the government, but few dentists seem to be doing so.
Mercury exposure, experts say, reaches the worst levels when old mercury fillings are drilled out, sending toxic particles flying in the breathing zones of patients, dentists and their aides. Many dentists use high-speed vacuums to suction most of the debris away from patients.
To see how high mercury exposures in dental offices could get, Hummell said he performed a two-day experiment at the office of Joe Palmer, a mercury-free dentist in Greenville, South Carolina, a few years ago. During drilling to remove a mercury filling in the mouth of a mannequin, he measured mercury levels as much as 30 times the OSHA limit.
“That’s drilling ‘high and dry,’ as they call it” – drilling out the filling and removing mercury particles with a high-speed suctioning device, Hummell said.
Several years ago, Hummell said he set up a booth at a regional dental conference in Denver to demonstrate how his equipment could pick up rising mercury levels with a mere gentle brushing of a filling in an old tooth.
He said he also showed dentists an American Dental Association pamphlet urging them to periodically monitor their offices for mercury, a circular that mostly drew chuckles and ridicule from the dentists. “I got a call the day after the convention from the American Dental Association’s lawyer threatening to take me down if I didn’t stop using their publication,” Hummell said. “I said, ‘I thought the dental association wanted them to know.’ Right after that, you couldn’t find that publication anywhere. It disappeared from the internet.” – Greg Gordon
Tests suggest mercury in air at some dental clinics (courtesy of Mercury Instruments).