Environmental Protection Agency Issues Update on DEHP Worker Expo

The Environmental Protection Agency’s update on DEHP worker exposure may sound like the sort of announcement best enjoyed with safety goggles, a spreadsheet, and a heroic amount of coffee. Yet the details matter to manufacturers, industrial hygienists, employees, labor representatives, and anyone responsible for chemical safety.

Released on July 28, 2025, the EPA announcement highlighted a memorandum providing additional context for the occupational exposure assessment in the agency’s draft risk evaluation of di(2-ethylhexyl) phthalate, commonly known as DEHP. The memorandum did not quietly replace the assessment or produce a surprise new risk calculation. Instead, it supplied information that had not been clearly presented in the original draft, including estimates of potentially exposed workers, occupational non-users, personal breathing-zone samples, and monitoring results reported as non-detects.

That distinction is important. The update was mainly about making the occupational-exposure record easier to understand. It answered questions such as: How many people could be affected in each work scenario? How many air samples supported the estimates? How did the EPA handle samples in which DEHP was below the laboratory’s detection limit?

What the EPA Actually Updated

The memorandum, dated July 24, 2025, focused on the occupational exposure scenarios used in the draft DEHP risk evaluation. An occupational exposure scenario, or OES, groups workplaces and activities expected to produce similar exposure patterns. Examples include DEHP manufacturing, plastics compounding, rubber-product manufacturing, repackaging, laboratory use, recycling, automotive-care applications, and waste handling.

For each applicable scenario, the EPA added estimates for three practical measurements:

• The number of workers who may directly handle DEHP or DEHP-containing materials.
• The number of occupational non-users who may be exposed without directly handling the chemical.
• The approximate number of facilities associated with the scenario.

The memorandum also explained the inhalation-monitoring information behind certain exposure estimates. It identified the number of personal breathing-zone samples, the number of non-detects, the use of surrogate data, and the scenarios for which modeling was necessary because suitable workplace measurements were unavailable.

Workers and Occupational Non-Users Are Not the Same

In the EPA’s framework, a worker may pour, mix, transfer, apply, clean up, or otherwise handle a material containing DEHP. An occupational non-user, often shortened to ONU, does not directly perform the DEHP-related task but works close enough to experience indirect exposure.

An ONU could be a supervisor walking through a production area, a maintenance technician servicing nearby equipment, a quality-control employee collecting records, or a warehouse worker stationed near an active process. The chemical does not check job titles before traveling through air or settling on surfaces. Rude, but chemically predictable.

Whether an ONU is exposed can depend on room dimensions, ventilation, barriers, process enclosure, employee movement, dust generation, mist formation, and the distance between the person and the source. Two facilities performing the same basic operation may therefore have very different exposure profiles.

What Is DEHP and Where Is It Used?

DEHP is a colorless, oily liquid primarily used as a plasticizer. Plasticizers are added to materials such as polyvinyl chloride, or PVC, to make them softer and more flexible. DEHP has also been associated with adhesives, sealants, coatings, rubber, resins, textiles, automotive products, laboratory chemicals, and other industrial or commercial applications.

EPA reporting data previously placed aggregate U.S. production volume between 100 million and 250 million pounds for 2015. Although product formulations and markets change over time, that historical range illustrates why DEHP is not an obscure chemical encountered by three chemists in a basement laboratory.

DEHP has very low vapor pressure, so a workplace exposure assessment cannot focus only on conventional vapor. Inhalation may involve aerosols, process mist, contaminated dust, or particles generated during mixing, heating, finishing, cutting, grinding, handling, and cleanup. Skin contact may also contribute in tasks involving liquids, dusty surfaces, contaminated tools, or inadequate hygiene practices.

Key Worker Estimates in the EPA Memorandum

The EPA used information from sources such as the Toxics Release Inventory, National Emissions Inventory, Discharge Monitoring Reports, Chemical Data Reporting records, Bureau of Labor Statistics data, Census data, industry classifications, and exposure-scenario documents. When direct site or market information was unavailable, the agency used modeling and other estimation methods.

Some modeled categories produced much larger ranges. For automotive-care products, for example, the memorandum presented a central-tendency estimate of 176,190 exposed workers and 25,170 ONUs, with high-end estimates exceeding one million workers and 147,000 ONUs. Laboratory-use estimates also varied dramatically depending on whether the EPA used central-tendency or high-end modeling assumptions.

Those figures should not be treated as a precise national headcount or casually added together. Employees, facilities, and activities may overlap across scenarios, while modeled high-end values are designed to explore plausible upper ranges rather than predict the exact number of people who will be exposed on a particular Tuesday.

Why the Headcounts Matter

The EPA stated that adding worker and ONU estimates did not change the underlying risk evaluation. However, population estimates can influence later risk-management decisions. A measure affecting 100 specialized employees at three facilities creates different implementation questions from one affecting hundreds of thousands of technicians, laboratory employees, or automotive workers.

Headcounts can help regulators evaluate the scale of a risk, the feasibility of controls, the number of businesses affected, the availability of substitutes, training needs, compliance costs, and whether protections should be tailored to specific conditions of use.

Understanding Non-Detects in DEHP Air Sampling

A non-detect does not necessarily mean that no DEHP was present. It means the analytical procedure did not measure DEHP above its applicable detection limit. The actual concentration could have been zero, just below the limit, or somewhere lower within the method’s unresolved range.

For DEHP manufacturing, the EPA identified 45 personal breathing-zone samples, 37 of which were non-detects. For plastics converting, four of 35 samples were non-detects. Plastics-compounding data included 21 samples with no reported non-detects, while some scenarios relied on only one sample, summary statistics, surrogate measurements, or exposure models.

For the manufacturing and plastics-converting datasets, the EPA incorporated non-detects into its calculations using one-half of the relevant detection limit. This prevents every non-detect from being treated as zero, an assumption that could underestimate exposure. It also avoids pretending that the instrument measured a precise concentration when it did not.

Not Every Scenario Had Its Own Monitoring Data

Of the 17 occupational scenarios evaluated for inhalation exposure, six had scenario-specific personal breathing-zone samples. Five used measurements from a similar scenario as surrogate data. Two relied on industry-relevant summary statistics, while four were assessed with empirically informed models because neither adequate personal samples nor suitable surrogates were available.

Surrogate data and modeling are common tools in chemical risk assessment, particularly when national workplace-monitoring databases are incomplete. They are useful, but they introduce uncertainty. A model is not a photograph of every factory; it is a structured estimate assembled from assumptions, available evidence, and mathematical relationships.

Did the Update Change the EPA’s DEHP Risk Findings?

No. The July 2025 memorandum explicitly stated that its additional sampling details did not affect the inhalation-exposure estimates in the draft risk evaluation. It was intended to improve transparency and provide information for public comment, scientific peer review, and eventual risk management.

The regulatory story continued after that memorandum. The draft evaluation had preliminarily identified unreasonable worker risk for 13 conditions of use. Following public comments and review by the Science Advisory Committee on Chemicals, the EPA completed its final DEHP risk evaluation in December 2025 and formally announced its availability in January 2026.

In the final evaluation, the EPA determined that DEHP presents an unreasonable risk to human health based on risks to workers from 10 conditions of use. It also identified unreasonable environmental risk from 20 conditions of use. The agency did not identify unreasonable human-health risk for consumers or the general population under the evaluated conditions of use.

The change from 13 preliminary worker findings to 10 final findings shows why a draft should not be reported as though it were the last word. Peer review, revised calculations, public submissions, and supporting evidence can change the final determination.

Health Concerns Associated With DEHP

Federal toxicology reviews have examined developmental, reproductive, liver, kidney, and cancer-related effects associated with DEHP. Much of the strongest controlled evidence comes from animal studies, so descriptions of human risk must preserve the difference between demonstrated animal effects, occupational observations, biomonitoring associations, and proven clinical outcomes.

The National Toxicology Program lists DEHP as reasonably anticipated to be a human carcinogen based on sufficient evidence from experimental animals. Reproductive and developmental effects, including effects on the male reproductive system in laboratory animals, have also played an important role in federal assessments of DEHP and related phthalates.

ATSDR reports that workers in facilities making or using PVC products may experience greater DEHP exposure than the general population, especially through inhalation. Occupational biomonitoring research reviewed by ATSDR found higher levels of DEHP metabolites among employees in PVC-film manufacturing, PVC compounding, and rubber-boot manufacturing than among the general population.

Federal agencies regulate different DEHP uses through different laws. OSHA and NIOSH materials identify an occupational eight-hour time-weighted exposure limit of 5 milligrams per cubic meter. The Consumer Product Safety Improvement Act permanently restricts DEHP above 0.1 percent in accessible plasticized components of children’s toys and child-care articles. FDA and EPA programs separately address areas such as food-contact materials, medical products, and drinking water.

Why an OSHA Limit and a TSCA Finding Are Different

An OSHA permissible exposure limit is a workplace compliance standard. A TSCA risk evaluation considers hazards, exposure routes, durations, potentially susceptible populations, and defined conditions of use to determine whether a chemical presents unreasonable risk.

Consequently, being below an OSHA air limit does not automatically prove that every chronic or combined exposure evaluated under TSCA is risk-free. Conversely, an EPA unreasonable-risk finding does not mean every employee at every facility experiences the same exposure.

The EPA’s DEHP conclusions for affected worker uses did not assume routine use of personal protective equipment. The agency noted that appropriate PPE may reduce exposure and mitigate risk, but effective chemical control should not begin and end with handing someone gloves and wishing them luck.

What Employers Can Do Before a New Risk-Management Rule

The final risk evaluation is not itself a ban or a complete set of new workplace instructions. Under TSCA, the EPA’s next phase is risk management, during which it is expected to propose regulatory measures focused on the conditions of use that significantly contribute to unreasonable risk.

Employers do not need to wait for that process before reviewing their chemical-safety programs. Sensible actions include:

• Inventory DEHP uses: Review raw materials, mixtures, PVC components, adhesives, coatings, rubber compounds, maintenance supplies, and waste streams.
• Check safety data and supplier information: Confirm concentrations and identify products marketed under unfamiliar trade names.
• Evaluate substitutes: Determine whether a less hazardous plasticizer or material can perform the same function without creating a different safety problem.
• Prioritize engineering controls: Enclose transfer points, improve local exhaust ventilation, reduce aerosol generation, and automate high-contact tasks where practical.
• Improve housekeeping: Use methods that capture contaminated dust instead of launching it back into the air with dry sweeping or compressed air.
• Collect representative exposure data: Sample normal production, maintenance, cleaning, startups, shutdowns, and unusual high-output tasks.
• Include occupational non-users: Examine employees working near a process, not only the person holding the hose, scoop, or spray gun.
• Use suitable PPE: Select gloves, protective clothing, eye protection, and respiratory protection through a documented hazard assessment and recognized protection program.

Practical Experience: Lessons From Realistic Workplace Scenarios

One of the most useful lessons from occupational-exposure work is that the obvious operator is not always the only person who matters. Consider a composite PVC-compounding facility where an employee feeds additives into an enclosed mixer. Management may initially conclude that the process is well controlled because the operator stands behind a partial enclosure and wears gloves.

A walkthrough can tell a more complicated story. Fine residue collects around bag-opening stations. A maintenance employee removes clogged material without local exhaust. Forklift traffic disturbs settled dust. A supervisor spends only 20 minutes in the area but returns several times each shift. The operator’s exposure may be modest while intermittent tasks and nearby movement create less predictable exposures for other employees.

The practical response is not to panic or purchase the largest respirator catalog available. It is to map the work. Who opens containers? Who cleans spills? Who changes filters? Where does dust settle? Which task creates visible mist? Does the ventilation system capture material at the source, or merely rearrange the room’s atmosphere?

A second composite example involves a rubber-products operation. Production measurements may represent routine mixing, yet maintenance crews enter equipment during shutdowns and encounter residue that accumulated over weeks. A full-shift production average can miss a short, high-contact repair task. Task-based sampling, surface evaluation, improved cleanout procedures, and controlled access may reveal more than another generic annual air sample.

Laboratories present a different challenge. The EPA memorandum’s broad modeled ranges reflect the difficulty of determining how many facilities use DEHP, how frequently they use it, and in what quantities. One laboratory may handle milliliter-scale reference standards in a fume hood. Another may use larger volumes in material testing. Treating those workplaces as identical would be convenient, but convenience is not an exposure metric.

Automotive-care applications create similar variability. A technician applying an undercoating in a ventilated commercial booth does not have the same exposure profile as someone using a small amount of product outdoors. Product composition, spray pressure, work duration, enclosure, temperature, and ventilation all matter. Good assessments document these differences instead of hiding them beneath a single national average.

Another recurring lesson is that non-detects must be explained carefully. Employees may hear “not detected” and understandably translate it as “none.” Industrial hygienists know that the statement really means “not measured above this method’s detection limit under these sampling conditions.” Communicating that distinction builds trust and prevents both false reassurance and unnecessary alarm.

Finally, exposure reviews work better when employees participate. Operators know which valve leaks, which bag tears, which fan is usually switched off because it is noisy, and which cleanup task creates the mysterious cloud everyone pretends not to notice. Monitoring data are strongest when paired with firsthand knowledge of how the job is actually performednot merely how the procedure manual imagines it is performed.

Why the EPA Update Matters

The DEHP worker-exposure memorandum demonstrates why transparency is a practical component of chemical regulation. Risk estimates are easier to evaluate when stakeholders can see how many samples were available, how non-detects were handled, which scenarios relied on surrogate information, and how large the potentially exposed workforce may be.

The update also reinforces a basic occupational-health principle: exposure is not limited to the employee directly touching a chemical. Nearby workers, maintenance personnel, cleaners, inspectors, and supervisors may belong in the assessment. Ignoring them because their job description does not contain the word “DEHP” would be an impressively tidy way to miss the point.

Conclusion

The Environmental Protection Agency’s DEHP worker-exposure update did not overturn the draft assessment or secretly rewrite its inhalation calculations. It added missing context about potentially exposed workers, occupational non-users, facility estimates, breathing-zone samples, non-detects, surrogate data, and modeled exposure scenarios.

That additional information helped support public review and the transition from the 2025 draft to the final risk evaluation completed later that year. The final assessment identified unreasonable worker risk from 10 conditions of use and environmental risk from 20 conditions of use. Risk-management rulemaking is the next major regulatory chapter.

For employers, the practical message is already clear: identify where DEHP is used, evaluate direct and indirect exposure, examine tasks rather than relying only on job titles, improve controls, collect representative measurements, and explain uncertainty honestly. A six-page memorandum may not look dramatic, but in chemical safety, the quiet details often decide whether protection exists on paper or on the production floor.

Note: The phrase “Worker Expo” in the supplied title has been interpreted as a shortened reference to “worker exposure.” This article reflects the EPA’s July 2025 memorandum and the final DEHP risk-evaluation status available through July 2026. It is informational and does not replace legal, medical, or site-specific industrial-hygiene advice.