Did some digging myself on it... From this I would assume at teh small amounts being used it would be ok.
MSDS on Soybean oil
http://www.steoil.com/pdfs/msds-soybeanoil.pdf
VI. HEALTH HAZARD DATA
INGESTION: NONE, MATERIAL IS A FOOD.
INHALATION: UNDER MIST CONDITIONS, NO SHORT TERM INHALATION LIMITS.
SKIN/EYE: FLUSH AND RINSE, PARTICULARLY FOR EYE CONTACT. NO SIGNIFICANT SKIN REACTION EXPECTED.
Health
Hazards
(Acute and
Chronic)
Route(s) of Entry Inhalation?
YES
Skin?
YES
Ingestion?
YES
Carcinogenicity NTP? N/A
IARC Monographs? N/A
OSHA Regulated?
Signs and Symptoms of Exposure Medical Conditions Generally Aggravated By Exposure N/A
NO N/A
N/A
Emergency and First Aid Procedures
EYES: FLUSH WITH WATER FOR AT LEAST 15 MINUTES
NO SPECIFIC HAZARDS; MATERIAL IS NON-HAZARDOUS; IF IN MIST FORM AND LEVELS ARE ABOVE 15MG/M3 (TOTAL), A DUST MASK
AND GOGGLES ARE RECOMMENDED.
Edit Found this also.. Testing done on exposure of mice to soybean oil based bio diesel.. Looks like no ill effects really at high exposures for prolonged terms..
Effects of subchronic inhalation exposure of rats ...[Inhal Toxicol. 2002] - PubMed Result