In our toxin-filled world, we often look to government agencies to tell us what levels of exposure we should consider safe or unsafe. If our exposure does not exceed an agency-determined threshold, we assume there is little cause for concern. How do regulatory agencies determine these thresholds? There is considerable evidence to suggest that safety limits are often arbitrary and do not accurately flag risks. A new study published in Environmental Research by a group of researchers in upstate New York underscores this point.