機器
accident
advertisement
alert
background
business
caution
company
construction
control
danger
dangerous
defense
design
employee
employment
environment
equipment
factory
first
harmful
hazard
health
industry
injury
job
law
notification
office
patient
prevention
process
protect
protection
regulation
risk
safe
safety
security
sign
site
sky
standard
transportation
warning
welfare
word
work
worker
workplace