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Patient services director Lexie O'Shea confirmed in a statement staff asked about smells in one of the seven new oral health units that arrived between March 2010 and April 2013.
''One or two staff members queried smells in one clinic when they first arrived, which was followed up and deemed to be due to the vans being new.''
The units were withdrawn this month for testing because of high levels of formaldehyde detected in a unit in Canterbury. Other health boards have also pulled vans off the road.
Testing finished on Thursday and laboratory results would take up to 15 days, Mrs O'Shea said.
The health board has already started a process to replace the suspended ceiling tiles thought to be the source of the contamination in the Canterbury unit.
University of Canterbury toxicologist Prof Ian Shaw said without knowing more about the manufacture of the ceiling tiles, it was unclear whether adverse health effects could result from the exposure. It was important employers adequately followed up staff complaints about unusual chemical smells in equipment or facilities, he said.
Prof Shaw said health fears about formaldehyde had reduced in recent years, but long-term exposure was potentially carcinogenic.