EPA legal limit
5 ppb
Maximum Contaminant Level
EWG health guideline
0.1 ppb
Science-based, stricter target
IARC classification
Group 1
Cancer research classification
Health effects
A known human carcinogen (IARC Group 1). Causes leukaemia and other blood cancers. There is no safe level of benzene exposure — the EWG health guideline of 0.1 ppb reflects a one-in-one-million cancer risk. The EPA MCL of 5 ppb is 50× higher than this threshold.
Where it comes from
Petroleum spills and leaking underground storage tanks (LUST sites) at gas stations. Industrial discharge. Naturally present in crude oil. Also a combustion byproduct that can enter water through atmospheric deposition.
How it's regulated
EPA MCL of 5 ppb. Classified as a known human carcinogen by EPA, IARC, and NTP. One of the six BTEX compounds (benzene, toluene, ethylbenzene, xylene) monitored at petroleum contamination sites.
The EPA vs EWG gap
The legal limit (5 ppb) is 50× higher than the EWG health guideline (0.1 ppb). Water can be legally compliant while still exceeding the science-based threshold.
How to filter benzene
Not all filters address benzene. Look for independently certified filters—NSF International certification means the removal claim has been independently verified.
Frequently asked questions
What is benzene?
A naturally occurring component of crude oil and a byproduct of combustion. One of the most studied carcinogens in drinking water. Found near petroleum storage sites, gas stations, and areas affected by fuel spills.
What are the health effects of benzene?
A known human carcinogen (IARC Group 1). Causes leukaemia and other blood cancers. There is no safe level of benzene exposure — the EWG health guideline of 0.1 ppb reflects a one-in-one-million cancer risk. The EPA MCL of 5 ppb is 50× higher than this threshold.
Is benzene regulated in drinking water?
EPA MCL of 5 ppb. Classified as a known human carcinogen by EPA, IARC, and NTP. One of the six BTEX compounds (benzene, toluene, ethylbenzene, xylene) monitored at petroleum contamination sites.
Where does benzene come from?
Petroleum spills and leaking underground storage tanks (LUST sites) at gas stations. Industrial discharge. Naturally present in crude oil. Also a combustion byproduct that can enter water through atmospheric deposition.
How do I remove benzene from tap water?
The most effective methods for removing benzene are: Activated carbon block filter, NSF 53 certified filter, Reverse osmosis (RO), NSF 58 certified RO system. Look for NSF-certified systems—independent certification confirms removal claims have been verified.
Is benzene in your water?
Enter your ZIP code to see the measured level in your specific utility.