Common sense practices can go a long way towards making your building and grounds safe for all who enter. First aid supplies, clear walkways, emergency contact information, and preventative maintenance of your heating and electrical systems are just some of the ways that congregations can ensure the basic safety of the physical plant. UUA.org has guideliness and resources to help guide you in this area.
An important partner for you in this area is your insurance company. Church Mutual has a wealth of written and video resources on a variety of topics. Most of the materials are available to anyone (a few of their resources require a password to access). If Church Mutual is not your provider, check with your insurance company to see what resources they have to offer. Most insurance companies take prevention and minimizing risk very seriously and are willing to work with you to prevent a potential problem from becoming a claim.