Ohio VAP Soil Standards - Volatile Organic Compounds (VOCs)

Overview

Ohio’s Voluntary Action Program (VAP) establishes generic direct-contact soil standards under OAC 3745-300-08. These are the numbers that consultants compare Phase II soil analytical results against to determine if a site meets cleanup requirements.

The standards below are from the current CIDARS database (February 2025 version, accompanying the VAP rules effective February 16, 2025). They represent the single-chemical generic direct-contact soil standard (GDCSS) - the lowest applicable value across all exposure pathways for each land use category.

Important distinction: These are direct-contact standards only. Soil can fail on other pathways even if direct-contact standards are met - particularly the soil-to-indoor-air pathway (vapor intrusion) and the soil leaching-to-groundwater pathway. A complete VAP evaluation requires screening against all applicable pathway standards, not just direct contact.

How the Standards Are Determined

The VAP generic soil standards are the lowest value from multiple exposure pathways evaluated for each chemical, land use, and receptor combination. For residential standards, this typically includes non-cancer risk, cancer risk, and soil saturation limits. The single-chemical GDCSS reported in CIDARS is the most restrictive value across all of these.

For VOCs, the residential soil standard is often driven by the vapor intrusion pathway (soil-to-indoor-air), which produces much lower values than the direct-contact ingestion/dermal pathway alone. This is why some VOC soil standards seem surprisingly low compared to what you might expect based on toxicity alone.

Residential Direct-Contact Soil Standards

These apply to properties with residential land use, including single-family homes, apartments, schools, and daycares.

Commercial/Industrial Direct-Contact Soil Standards

These apply to properties with commercial or industrial land use where workers are the primary receptors.

Contaminant	CAS Number	C/I GDCSS (mg/kg)	Construction Worker (mg/kg)
Benzene	71-43-2	130	130
Toluene	108-88-3	820	820
Ethylbenzene	100-41-4	480	480
Xylenes (total)	1330-20-7	260	260
Naphthalene	91-20-3	220	230
Trichloroethylene (TCE)	79-01-6	33	48
Tetrachloroethylene (PCE)	127-18-4	170	170
Vinyl Chloride	75-01-4	2.3	49
1,1-Dichloroethylene	75-35-4	1,200	1,200
cis-1,2-Dichloroethylene	156-59-2	880	2,400
MTBE	1634-04-4	5,400	5,400
1,2,4-Trimethylbenzene	95-63-6	220	220
1,3,5-Trimethylbenzene	108-67-8	180	180

Practical Notes for Consultants

Residential vs. Commercial/Industrial - When It Matters

The gap between residential and C/I standards varies enormously by contaminant. For BTEX compounds (benzene, toluene, ethylbenzene, xylenes), the residential and C/I numbers are within an order of magnitude of each other. But for chlorinated solvents like vinyl chloride, the residential standard (1.3 mg/kg) is almost 40 times lower than the construction worker standard (49 mg/kg). This means land-use classification has a huge impact at chlorinated solvent sites.

If your client is considering a land-use restriction to avoid residential standards, make sure they understand the long-term implications - use restrictions are recorded with the deed and affect property value and future flexibility.

Soil Saturation Limits

Several contaminants in the table above - toluene (820 mg/kg), xylenes (260 mg/kg), PCE (170 mg/kg), and the trimethylbenzenes - have residential standards that are actually driven by the soil saturation concentration, not by a risk calculation. Soil saturation is the maximum concentration a soil can hold before the contaminant exists as a separate phase (NAPL). When you see the residential and C/I standards at the same value, it’s usually because both are capped at soil saturation.

Vapor Intrusion - The Hidden Driver

For most VOCs, the soil-to-indoor-air pathway produces the most restrictive cleanup standard. The GDCSS values in the tables above already account for this, but it’s worth understanding because it affects how you design your sampling program. If you’re only collecting soil samples for direct-contact analysis and not evaluating the vapor intrusion pathway separately, you’re missing the pathway that’s most likely to drive cleanup at a VOC site.

Ohio’s vapor intrusion screening levels are derived from the CIDARS indoor air standards combined with attenuation factors. See our Ohio Vapor Intrusion Screening Levels page for the specific numbers.

VAP vs. BUSTR Soil Standards

If you’re working at a petroleum UST site regulated by BUSTR (OAC 1301:7-9), be aware that BUSTR has its own set of soil action levels that are different from the VAP standards. The BUSTR closure action levels (Table 2.3 of the BUSTR TGM) are specifically designed for petroleum UST closure assessments and assume residential land use, drinking water groundwater, and less than 15 feet to groundwater. They are not interchangeable with VAP standards.

For a comparison, see our Ohio BUSTR Corrective Action Standards page.

PID Screening in the Field

When collecting soil samples for VOC analysis, field screen every sample interval with a PID (photoionization detector). The PID reading helps you identify the most contaminated intervals for laboratory analysis and provides real-time information about VOC distribution. Use a 10.6 eV lamp for BTEX compounds - the 11.7 eV lamp detects more compounds but is less selective.

PID readings are not a substitute for laboratory analysis, but they’re invaluable for directing your sampling program and avoiding the expensive mistake of sending the wrong samples to the lab.

Sample Collection for VOCs

Soil samples for VOC analysis require special handling to prevent volatile losses:

• Use EnCore samplers or equivalent - these are sealed, zero-headspace containers that preserve VOCs from the moment of collection
• Alternatively, use brass or stainless steel sleeves sealed with PTFE caps and shipped on ice
• Collect samples from the freshly exposed face immediately after advancing the boring - don’t let the soil sit exposed to air
• Do not composite soil samples for VOC analysis - each sample must be a discrete grab from a specific depth
• Maintain chain of custody and ship on ice to the lab within the method-specified holding time

Comparison with EPA Regional Screening Levels

The Ohio VAP soil standards are generally similar to but not identical to EPA’s Regional Screening Levels (RSLs). Key differences include the exposure factors used (Ohio uses its own parameters in some cases), the toxicity values applied (Ohio follows its own hierarchy), and the specific pathways evaluated. When both a VAP standard and an RSL exist for the same contaminant, use the VAP standard for Ohio VAP sites.

For non-VAP work (federal Superfund, due diligence screening), see our EPA RSL Tables - 2026 Update Explained (coming soon) page.

Related Resources

• Ohio VAP Groundwater Standards - VOCs - Companion groundwater standards
• Ohio VAP Program Overview - How the VAP works
• Ohio Vapor Intrusion Screening Levels - Indoor air and sub-slab standards
• Soil Sampling Techniques for ESAs (coming soon) - Field guide for collecting valid soil samples
• Ohio BUSTR Corrective Action Standards - Separate standards for petroleum UST sites